Posts Tagged ‘root directory’

Find largest files on AIX system root / show biggest files and directories in AIX folder howto

Friday, November 6th, 2020

ibm-aix-logo-find-largest-files-and-directories-on-system-to-free-space-if-disk-is-full

On an AIX server if you get a root directory ( / ) to be completely full problem and the AIX running services are unable to write their pid files and logs for example in /tmp /admin /home /var/tmp /var/log/ and rest of directory structure or the system is almost full with mounted filesystems which shows it is 90% or 95%+ full on main partition,  the system is either already stuck or it is on the way to stop functiononing normally. Hence the only way to recover IBM AIX machine to a normal behavior is to clean up some files (if you can't extend the partition) or add more physical Hard drive, just as we usually do on Linux.

So How can we clean up largest files on AIX?


Lets say we want to find all files on AIX larger than 1 MB.

aix-system:/ $ find / -xdev -size 2048 -ls | sort -r +6
12579 1400 -rw-r—–  1 root      security   1433534 Jun 26  2019 /etc/security/tsd/tsd.dat
 9325 20361 -rw-r—–  1 root      system    20848752 Nov  6 16:02 /etc/security/failedlogin
21862 7105 -rwxr-xr-x  1 root      system     7274915 Aug 24  2017 /sbin/zabbix_agentd
   72 7005 -rw-rw—-  1 root      system     7172962 Nov  6 16:19 /audit/stream.out
24726 2810 -rw——-  1 root      system     2876944 Feb 29  2012 /etc/syslog-ng/core
29314 2391 -r-xr-xr-x  1 root      system     2447454 Jun 25  2019 /lpp/bos/bos.rte.filesystem/7.1.5.32.save/update.16
21844 2391 -r-xr-xr-x  1 root      system     2447414 Jun 25  2019 /sbin/helpers/jfs2/logredo64
21843 2219 -r-xr-xr-x  1 root      system     2271971 Jun 25  2019 /sbin/helpers/jfs2/logredo
29313 2218 -r-xr-xr-x  1 root      system     2270835 Jun 25  2019 /lpp/bos/bos.rte.filesystem/7.1.5.32.save/update.15
22279 1800 -rw-r–r–  1 root      system     1843200 Nov  4 08:03 /root/smit.log
12577 1399 -rw-r–r–  1 root      system     1431685 Jun 26  2019 /etc/security/tsd/.tsd.bk
21837 1325 -r-xr-xr-x  1 root      system     1356340 Jun 25  2019 /sbin/helpers/jfs2/fsck64
29307 1325 -r-xr-xr-x  1 root      system     1356196 Jun 25  2019 /lpp/bos/bos.rte.filesystem/7.1.5.32.save/update.9
   12 1262 -rw——-  1 root      system     1291365 Aug  8  2011 /core

 

Above finds all files greater than 1 MB and sort them in reverse
order with the largest files first.

To search all files larger than 64 Megabytes under root ( / )

aix-system:/ $ find / -xdev -size +131072 -ls | sort -r +6
65139 97019 -rw-r–r–  1 root      system    99347181 Mar 31  2017 /admin/archive.zip


Display 10 largest directories on system

aix-system:/ $ du -a /dir | sort -n -r | head -10


Show biggest files and directories in a directory

 

aix-system:/ $ du -sk * | sort -n
4       Mail
4       liste
4       my_user
4       syslog-ng.conf
140     smit.script
180     smit.transaction
1804    smit.log

Below du display the size of all files and directories in the current directory with the biggest being at the bottom.

 

List all largest files in dir decrasingly. If a directory is matches show all sub-dirs largest files.

aix-system:/ $ ls -A . | while read name; do du -sk $name; done | sort -nr

Below ls + while loop command sorts disk usage for all files in the current directory by size, in decreasing order. If the file we suspect happens to be a directory, we can then change into that directory, and re-run the preceding command to determine what is taking up space within that directory.

Continue these steps until you find the desired file or files, at which point you can take appropriate actions.

If the bottom-most item is a directory, then cd into that directory and run the du command again. Keep drilling down until you find the biggest files on your system and get rid of them to save some space.

Reinstall all Debian packages with a copy of apt deb package list from another working Debian Linux installation

Wednesday, July 29th, 2020

Reinstall-all-Debian-packages-with-copy-of-apt-packages-list-from-another-working-Debian-Linux-installation

Few days ago, in the hurry in the small hours of the night, I've done something extremely stupid. Wanting to move out a .tar.gz binary copy of qmail installation to /var/lib/qmail with all the dependent qmail items instead of extracting to admin user /root directory (/root), I've extracted it to the main Operating system root / directrory.
Not noticing this, I've quickly executed rm -rf var with the idea to delete all directory tree under /root/var just 3 seconds later, I've realized I'm issuing the rm -rf var with the wrong location WITH a root user !!!! Being scared on what I've done, I've quickly pressed CTRL+C to immedately cancel the deletion operation of my /var.

wrong-system-var-rm-linux-dont-do-that-ever-or-your-system-will-end-up-irreversably-damaged

But as you can guess, since the machine has an Slid State Drive drive and SSD memory drive are much more faster in I/O operations than the classical ATA / SATA disks. I was not quick enough to cancel the operation and I've noticed already some part of my /var have been R.I.P-pped in the heaven of directories.

This was ofcourse upsetting so for a while I rethinked the situation to get some ideas on what I can do to recover my system ASAP!!! and I had the idea of course to try to reinstall All my installed .deb debian packages to restore system closest to the normal, before my stupid mistake.

Guess my unpleasent suprise when I have realized dpkg and respectively apt-get apt and aptitude package management tools cannot anymore handle packages as Debian Linux's package dependency database has been damaged due to missing dpkg directory 

 

/var/lib/dpkg 

 

Oh man that was unpleasent, especially since I've installed plenty of stuff that is custom on my Mate based desktop and, generally reinstalling it updating the sytem to the latest Debian security updates etc. will be time consuming and painful process I wanted to omit.

So of course the logical thing to do here was to try to somehow recover somehow a database copy of /var/lib/dpkg  if that was possible, that of course led me to the idea to lookup for a way to recover my /var/lib/dpkg from backup but since I did not maintained any backup copy of my OS anywhere that was not really possible, so anyways I wondered whether dpkg does not keep some kind of database backups somewhere in case if something goes wrong with its database.
This led me to this nice Ubuntu thred which has pointed me to the part of my root rm -rf dpkg db disaster recovery solution.
Luckily .deb package management creators has thought about situation similar to mine and to give the user a restore point for /var/lib/dpkg damaged database

/var/lib/dpkg is periodically backed up in /var/backups

A typical /var/lib/dpkg on Ubuntu and Debian Linux looks like so:
 

hipo@jeremiah:/var/backups$ ls -l /var/lib/dpkg
total 12572
drwxr-xr-x 2 root root    4096 Jul 26 03:22 alternatives
-rw-r–r– 1 root root      11 Oct 14  2017 arch
-rw-r–r– 1 root root 2199402 Jul 25 20:04 available
-rw-r–r– 1 root root 2199402 Oct 19  2017 available-old
-rw-r–r– 1 root root       8 Sep  6  2012 cmethopt
-rw-r–r– 1 root root    1337 Jul 26 01:39 diversions
-rw-r–r– 1 root root    1223 Jul 26 01:39 diversions-old
drwxr-xr-x 2 root root  679936 Jul 28 14:17 info
-rw-r—– 1 root root       0 Jul 28 14:17 lock
-rw-r—– 1 root root       0 Jul 26 03:00 lock-frontend
drwxr-xr-x 2 root root    4096 Sep 17  2012 parts
-rw-r–r– 1 root root    1011 Jul 25 23:59 statoverride
-rw-r–r– 1 root root     965 Jul 25 23:59 statoverride-old
-rw-r–r– 1 root root 3873710 Jul 28 14:17 status
-rw-r–r– 1 root root 3873712 Jul 28 14:17 status-old
drwxr-xr-x 2 root root    4096 Jul 26 03:22 triggers
drwxr-xr-x 2 root root    4096 Jul 28 14:17 updates

Before proceeding with this radical stuff to move out /var/lib/dpkg/info from another machine to /var mistakenyl removed oned. I have tried to recover with the well known:

  • extundelete
  • foremost
  • recover
  • ext4magic
  • ext3grep
  • gddrescue
  • ddrescue
  • myrescue
  • testdisk
  • photorec

Linux file deletion recovery tools from a USB stick loaded with a Number of LiveCD distributions, i.e. tested recovery with:

  • Debian LiveCD
  • Ubuntu LiveCD
  • KNOPPIX
  • SystemRescueCD
  • Trinity Rescue Kit
  • Ultimate Boot CD


but unfortunately none of them couldn't recover the deleted files … 

The reason why the standard file recovery tools could not recover ?

My assumptions is after I've done by rm -rf var; from sysroot,  issued the sync (- if you haven't used it check out man sync) command – that synchronizes cached writes to persistent storage and did a restart from the poweroff PC button, this should have worked, as I've recovered like that in the past) in a normal Sys V System with a normal old fashioned blocks filesystem as EXT2 . or any other of the filesystems without a journal, however as the machine run a EXT4 filesystem with a journald and journald, this did not work perhaps because something was not updated properly in /lib/systemd/systemd-journal, that led to the situation all recently deleted files were totally unrecoverable.

1. First step was to restore the directory skele of /var/lib/dpkg

# mkdir -p /var/lib/dpkg/{alternatives,info,parts,triggers,updates}

 

2. Recover missing /var/lib/dpkg/status  file

The main file that gives information to dpkg of the existing packages and their statuses on a Debian based systems is /var/lib/dpkg/status

# cp /var/backups/dpkg.status.0 /var/lib/dpkg/status

 

3. Reinstall dpkg package manager to make package management working again

Say a warm prayer to the Merciful God ! and do:

# apt-get download dpkg
# dpkg -i dpkg*.deb

 

4. Reinstall base-files .deb package which provides basis of a Debian system

Hopefully everything will be okay and your dpkg / apt pair will be in normal working state, next step is to:

# apt-get download base-files
# dpkg -i base-files*.deb

 

5. Do a package sanity and consistency check and try to update OS package list

Check whether packages have been installed only partially on your system or that have missing, wrong or obsolete control  data  or  files.  dpkg  should suggest what to do with them to get them fixed.

# dpkg –audit

Then resynchronize (fetch) the package index files from their sources described in /etc/apt/sources.list

# apt-get update


Do apt db constistency check:

#  apt-get check


check is a diagnostic tool; it updates the package cache and checks for broken dependencies.
 

Take a deep breath ! …

Do :

ls -l /var/lib/dpkg
and compare with the above list. If some -old file is not present don't worry it will be there tomorrow.

Next time don't forget to do a regular backup with simple rsync backup script or something like Bacula / Amanda / Time Vault or Clonezilla.
 

6. Copy dpkg database from another Linux system that has a working dpkg / apt Database

Well this was however not the end of the story … There were still many things missing from my /var/ and luckily I had another Debian 10 Buster install on another properly working machine with a similar set of .deb packages installed. Therefore to make most of my programs still working again I have copied over /var from the other similar set of package installed machine to my messed up machine with the missing deleted /var.

To do so …
On Functioning Debian 10 Machine (Working Host in a local network with IP 192.168.0.50), I've archived content of /var:

linux:~# tar -czvf var_backup_debian10.tar.gz /var

Then sftped from Working Host towards the /var deleted broken one in my case this machine's hostname is jericho and luckily still had SSHD and SFTP running processes loaded in memory:

jericho:~# sftp root@192.168.0.50
sftp> get var_backup_debian10.tar.gz

Now Before extracting the archive it is a good idea to make backup of old /var remains somewhere for example somewhere in /root 
just in case if we need to have a copy of the dpkg backup dir /var/backups

jericho:~# cp -rpfv /var /root/var_backup_damaged

 
jericho:~# tar -zxvf /root/var_backup_debian10.tar.gz 
jericho:/# mv /root/var/ /

Then to make my /var/lib/dpkg contain the list of packages from my my broken Linux install I have ovewritten /var/lib/dpkg with the files earlier backupped before  .tar.gz was extracted.

jericho:~# cp -rpfv /var /root/var_backup_damaged/lib/dpkg/ /var/lib/

 

7. Reinstall All Debian  Packages completely scripts

 

I then tried to reinstall each and every package first using aptitude with aptitude this is done with

# aptitude reinstall '~i'

However as this failed, tried using a simple shell loop like below:

for i in $(dpkg -l |awk '{ print $2 }'); do echo apt-get install –reinstall –yes $i; done

Alternatively, all .deb package reninstall is also possible with dpkg –get-selections and with awk with below cmds:

dpkg –get-selections | grep -v deinstall | awk '{print $1}' > list.log;
awk '$1=$1' ORS=' ' list.log > newlist.log
;
apt-get install –reinstall $(cat newlist.log)

It can also be run as one liner for simplicity:

dpkg –get-selections | grep -v deinstall | awk '{print $1}' > list.log; awk '$1=$1' ORS=' ' list.log > newlist.log; apt-get install –reinstall $(cat newlist.log)

This produced a lot of warning messages, reporting "package has no files currently installed" (virtually for all installed packages), indicating a severe packages problem below is sample output produced after each and every package reinstall … :

dpkg: warning: files list file for package 'iproute' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'brscan-skey' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libapache2-mod-php7.4' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libexpat1:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libexpat1:i386' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'php5.6-readline' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'linux-headers-4.19.0-5-amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libgraphite2-3:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libgraphite2-3:i386' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libbonoboui2-0:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libxcb-dri3-0:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libxcb-dri3-0:i386' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'liblcms2-2:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'liblcms2-2:i386' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libpixman-1-0:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libpixman-1-0:i386' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'gksu' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'liblogging-stdlog0:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'mesa-vdpau-drivers:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'mesa-vdpau-drivers:i386' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libzvbi0:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libzvbi0:i386' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libcdparanoia0:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libcdparanoia0:i386' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'python-gconf' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'php5.6-cli' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'libpaper1:amd64' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'mixer.app' missing; assuming package has no files currently installed

After some attempts I found a way to be able to work around the warning message, for each package by simply reinstalling the package reporting the issue with

apt –reinstall $package_name


Though reinstallation started well and many packages got reinstalled, unfortunately some packages such as apache2-mod-php5.6 and other php related ones  started failing during reinstall ending up in unfixable states right after installation of binaries from packages was successfully placed in its expected locations on disk. The failures occured during the package setup stage ( dpkg –configure $packagename) …

The logical thing to do is a recovery attempt with something like the usual well known by any Debian admin:

apt-get install –fix-missing

As well as Manual requesting to reconfigure (issue re-setup) of all installed packages also did not produced a positive result

dpkg –configure -a

But many packages were still failing due to dpkg inability to execute some post installation scripts from respective .deb files.
To work around that and continue installing the rest of packages I had to manually delete all files related to the failing package located under directory 

/var/lib/dpkg/info#

For example to omit the post installation failure of libapache2-mod-php5.6 and have a succesful install of the package next time I tried reinstall, I had to delete all /var/lib/dpkg/info/libapache2-mod-php5.6.postrm, /var/lib/dpkg/info/libapache2-mod-php5.6.postinst scripts and even sometimes everything like libapache2-mod-php5.6* that were present in /var/lib/dpkg/info dir.

The problem with this solution, however was the package reporting to install properly, but the post install script hooks were still not in placed and important things as setting permissions of binaries after install or applying some configuration changes right after install was missing leading to programs failing to  fully behave properly or even breaking up even though showing as finely installed …

The final solution to this problem was radical.
I've used /var/lib/dpkg database (directory) from ther other working Linux machine with dpkg DB OK found in var_backup_debian10.tar.gz (linux:~# host with a working dpkg database) and then based on the dpkg package list correct database responding on jericho:~# to reinstall each and every package on the system using Debian System Reinstaller script taken from the internet.
Debian System Reinstaller works but to reinstall many packages, I've been prompted again and again whether to overwrite configuration or keep the present one of packages.
To Omit the annoying [Y / N ] text prompts I had made a slight modification to the script so it finally looked like this:
 

#!/bin/bash
# Debian System Reinstaller
# Copyright (C) 2015 Albert Huang
# Copyright (C) 2018 Andreas Fendt

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# —
# This script assumes you are using a Debian based system
# (Debian, Mint, Ubuntu, #!), and have sudo installed. If you don't
# have sudo installed, replace "sudo" with "su -c" instead.

pkgs=`dpkg –get-selections | grep -w 'install$' | cut -f 1 |  egrep -v '(dpkg|apt)'`

for pkg in $pkgs; do
    echo -e "\033[1m   * Reinstalling:\033[0m $pkg"    

    apt-get –reinstall -o Dpkg::Options::="–force-confdef" -o Dpkg::Options::="–force-confold" -y install $pkg || {
        echo "ERROR: Reinstallation failed. See reinstall.log for details."
        exit 1
    }
done

 

 debian-all-packages-reinstall.sh working modified version of Albert Huang and Andreas Fendt script  can be also downloaded here.

Note ! Omitting the text confirmation prompts to install newest config or keep maintainer configuration is handled by the argument:

 

-o Dpkg::Options::="–force-confold


I however still got few NCurses Console selection prompts during the reinstall of about 3200+ .deb packages, so even with this mod the reinstall was not completely automatic.

Note !  During the reinstall few of the packages from the list failed due to being some old unsupported packages this was ejabberd, ircd-hybrid and a 2 / 3 more.
This failure was easily solved by completely purging those packages with the usual

# dpkg –purge $packagename

and reruninng  debian-all-packages-reinstall.sh on each of the failing packages.

Note ! The failing packages were just old ones left over from Debian 8 and Debian 9 before the apt-get dist-upgrade towards 10 Duster.
Eventually I got a success by God's grance, after few hours of pains and trials, ending up in a working state package database and a complete set of freshly reinstalled packages.

The only thing I had to do finally is 2 hours of tampering why GNOME did not automatically booted after the system reboot due to failing gdm
until I fixed that I've temprary used ligthdm (x-display-manager), to do I've

dpkg –reconfigure gdm3

lightdm-x-display-manager-screenshot-gdm3-reconfige

 to work around this I had to also reinstall few libraries, reinstall the xorg-server, reinstall gdm and reinstall the meta package for GNOME, using below set of commands:
 

apt-get install –reinstall libglw1-mesa libglx-mesa0
apt-get install –reinstall libglu1-mesa-dev
apt install –reinstallgsettings-desktop-schemas
apt-get install –reinstall xserver-xorg-video-intel
apt-get install –reinstall xserver-xorg
apt-get install –reinstall xserver-xorg-core
apt-get install –reinstall task-desktop
apt-get install –reinstall task-gnome-desktop

 

As some packages did not ended re-instaled on system because on the original host from where /var/lib/dpkg db was copied did not have it I had to eventually manually trigger reinstall for those too:

 

apt-get install –reinstall –yes vlc
apt-get install –reinstall –yes thunderbird
apt-get install –reinstall –yes audacity
apt-get install –reinstall –yes gajim
apt-get install –reinstall –yes slack remmina
apt-get install –yes k3b
pt-get install –yes gbgoffice
pt-get install –reinstall –yes skypeforlinux
apt-get install –reinstall –yes vlc
apt-get install –reinstall –yes libcurl3-gnutls libcurl3-nss
apt-get install –yes virtualbox-5.2
apt-get install –reinstall –yes vlc
apt-get install –reinstall –yes alsa-tools-gui
apt-get install –reinstall –yes gftp
apt install ./teamviewer_15.3.2682_amd64.deb –yes

 

Note that some of above packages requires a properly configured third party repositories, other people might have other packages that are missing from the dpkg list and needs to be reinstalled so just decide according to your own case of left aside working system present binaries that doesn't belong to any dpkg installed package.

After a bit of struggle everything is back to normal Thanks God! 🙂 !
 

 

Upgrade Debian Linux 9 to 10 Stretch to Buster and Disable graphical service load boot on Debian 10 Linux / Debian Buster is out

Tuesday, July 9th, 2019

howto-upgrade-debian-linux-debian-stretch-to-buster-debian-10-buster

I've just took a time to upgrade my Debian 9 Stretch Linux to Debian Buster on my old school Laptop (that turned 11 years old) Lenovo Thinkpad R61 . The upgrade went more or less without severe issues except few things.

The overall procedure followed is described n a few websites out there already and comes up to;

 

0. Set the proper repository location in /etc/apt/sources.list


Before update the sources.list used are:
 

deb [arch=amd64,i386] http://ftp.bg.debian.org/debian/ buster main contrib non-free
deb-src [arch=amd64,i386] http://ftp.bg.debian.org/debian/ buster main contrib non-free

 

deb [arch=amd64,i386] http://security.debian.org/ buster/updates main contrib non-free
deb-src [arch=amd64,i386] http://security.debian.org/ buster/updates main contrib non-free

deb [arch=amd64,i386] http://ftp.bg.debian.org/debian/ buster-updates main contrib non-free
deb-src [arch=amd64,i386] http://ftp.bg.debian.org/debian/ buster-updates main contrib non-free

deb http://ftp.debian.org/debian buster-backports main


For people that had stretch defined in /etc/apt/sources.list you should change them to buster or stable, easiest and quickest way to omit editting with vim / nano etc. is run as root or via sudo:
 

sed -i 's/stretch/buster/g' /etc/apt/sources.list
sed -i 's/stretch/buster/g' /etc/apt/sources.list.d/*.list

The minimum of config in sources.list after the modification should be
 

deb http://deb.debian.org/debian buster main
deb http://deb.debian.org/debian buster-updates main
deb http://security.debian.org/debian-security buster/updates main

Or if you want to always be with latest stable packages (which is my practice for notebooks):

deb http://deb.debian.org/debian stable main
deb http://deb.debian.org/debian stable-updates main
deb http://security.debian.org/debian-security stable/updates main

 

1. Getting list of hold packages if such exist and unholding them, e.g.

 

apt-mark showhold


Same could also be done via dpkg

dpkg –get-selections | grep hold


To unhold a package if such is found:

echo "package_name install"|sudo dpkg –set-selections

For those who don't know what hold package is this is usually package you want to keep at certain version all the time even though after running apt-get upgrade to get the latest package versions.
 

2. Use df -h and assure you have at least 5 – 10 GB free space on root directory / before proceed

df -h /

3. Update packages list to set new set repos as default

apt update

 

4. apt upgrade
 

apt upgrade

Here some 10 – 15 times you have to confirm what you want to do with configuration that has changed if you're unsure about the config (and it is not critical service) you're aware as such as Apache / MySQL / SMTP etc. it is best to install the latest maintainer version.

Hopefully here you will not get fatal errors that will interrupt it.

P.S. It is best to run apt-update either in VTTY (Virtual console session) with screen or tmux or via a physical tty (if this is not a remote server) as during the updates your GUI access to the gnome-terminal or konsole / xterm whatever console used might get cut. Thus it is best to do it with command:
 

screen apt upgrade

 

5. Run dist-upgrade to finalize the upgrade from Stertch to Buster

 

Once all is completed of the new installed packages, you will need to finally do, once again it is best to run via screen, if you don't have installed screen install it:

 

if [ $(which screen) ]; then echo 'Installed'; else apt-get install –yes screen ; fi

screen apt dist-upgrade


Here once again you should set whether old configuration to some e services has to stay or the new Debian maintainer package shipped one will overwrite the old and locally modified (due to some reason), here do wisely whatever you will otherwise some configured services might not boot as expected on next boot.

 

6. What if you get packages failed on update


If you get a certain package failed to configure after installed due to some reason, if it is a systemd service use:

 

journalctl -xe |head -n 50


or fully observer output of journalctl -xe and decide on yourself.

In most cases

dpkg-reconfigure failed-package-name


should do the trick or at least give you more hints on how to solve it.

 

Also if a package seems to be in inconsistent or broken state after upgrade  and simple dpkg-reconfigure doesn't help, a good command
that can help you is

 

dpkg-reconfigure -f package_name

 

or you can try to workaround a failed package setup with:
 

dpkg –configure -a

 
If dpkg-reconfigure doesn't help either as I experienced in prior of Debian from Debian 6 -> 7 an Debian 7 ->8 updates on some Computers, then a very useful thing to try is:
 

apt-get update –fix-missing 

apt-get install -f


At certain cases the only work around to be able to complete the package upgrade is to to remove the package with apt remove but due to config errors even that is not possible to work around this as final resort run:
 

dpkg –remove –force-remove-reinstreq

 

7. Clean up ununeeded packages

 

Some packages are left over due to package dependencies from Stretch and not needed in buster anymore to remove them.
 

apt autoremove

 

8. Reboot system once all upgrade is over

 

/sbin/reboot

 

9. Verify your just upgraded Debian is in a good state

 

root@noah:~# uname -a;
Linux noah 4.19.0-5-rt-amd64 #1 SMP PREEMPT RT Debian 4.19.37-5 (2019-06-19) x86_64 GNU/Linux

 

root@noah:~# cat /etc/issue.net
Debian GNU/Linux 10
 

 

root@noah:~# lsb_release -a
No LSB modules are available.
Distributor ID:    Debian
Description:    Debian GNU/Linux 10 (buster)
Release:    10
Codename:    buster

 

root@noah:~# hostnamectl
   Static hostname: noah
         Icon name: computer-laptop
           Chassis: laptop
        Machine ID: 4759d9c2f20265938692146351a07929
           Boot ID: 256eb64ffa5e413b8f959f7ef43d919f
  Operating System: Debian GNU/Linux 10 (buster)
            Kernel: Linux 4.19.0-5-rt-amd64
      Architecture: x86-64

 

10. Remove annoying picture short animation with debian logo looping

 

plymouth-debian-graphical-boot-services

By default Debian 10 boots up with annoying screen hiding all the status of loaded services state .e.g. you cannot see the services that shows in [ FAILED ] state and  which do show as [ OK ] to revert back the old behavior I'm used to for historical reasons and as it shows a lot of good Boot time debugging info, in previous Debian distributions this was possible  by setting the right configuration options in /etc/default/grub

which so far in my config was like so

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash scsi_mod.use_blk_mq=y dm_mod.use_blk_mq=y zswap.enabled=1 text"


Note that zswap.enabled=1 passed option is because my notebook is pretty old machine from 2008 with 4GB of memory and zswap does accelerate performance when working with swap – especially helpful on Older PCs for more you can read more about zswap on ArchLinux wiki
After modifying this configuration to load the new config into grub the cmd is:
 

/usr/sbin/update-grub

 
As this was not working and tried number of reboots finally I found that annoying animated gif like picture shown up is caused by plymouth below is excerpts from Plymouth's manual page:


       "The plymouth sends commands to a running plymouthd. This is used during the boot process to control the display of the graphical boot splash."

Plymouth has a set of themes one can set:

 

# plymouth-set-default-theme -l
futureprototype
details
futureprototype
joy
lines
moonlight
softwaves
spacefun
text
tribar

 

I tried to change that theme to make the boot process as text boot as I'm used to historically with cmd:
 

update-alternatives –config text.plymouth

 
As after reboot I hoped the PC will start booting in text but this does not happened so the final fix to turn back to textmode service boot was to completely remove plymouth
 

apt-get remove –yes plymouth

How to Increase virtualbox Linux install machine VM .VDI hard disk size to free space on root partition – Move /usr to a new partition

Tuesday, October 10th, 2017

extend-vdi-virtual-machine-partition-with-virtualbox-howto-virtualbox-logo
 

How to Increse Hard Disk size of VirtualBox Virtual Machine .VDI file to Free Space on root Partition or Howto move /usr large partition to separate new partition?


I just wondered how to increase hard disk size of Virtualbox Virtual Machine image .VDI, because for some stupid reason I've created my initial hard disk size for Linux partition to be the default 10 Gigabytes.

The problem is the packages I need to have installed on the Virtual Machine which will be a testbed for future tests of a production website applications are taking up too much space, once installed so I'm left with no space
in /var/lib/mysql for the database import. So what can I do in that case is to simply free up disk space or Merge ROOT partition with another partition.

Since merging the partition is not a trivial job and would require me to have installable CD with the Linux distro (in my case that's Debian Linux) or have a bootable USB flash drive, I preferred second approach to problem e.g. to free up disk space on ROOT partition by creating a second partition and move the /usr folder to reside there.

Before that it is of course necessery to  have extended the .VDI file using VirtualBox, so more space than the default 10GB preconfigured are available, this is easily done on Windows OS as, VBox is provided with GUI clickable option to do it, but for who knows what reason that is not the case with Linux, so Linux users only option to increase VDI file is to manually run command part of the virtualbox package, that is not a hard task really but it requires some typing and basic knowledge on how to run commands in terminal.


To .VDI resize (extend), we first go to default location where VirtualBox stores its image .VDI files (by default as of moment of writting this article – this is ~/"VrtualBox VMs"  (or home directory of logged in user dir VirtualBox VMs), the command to use is VBoxManage

 

root@jericho:/home/hipo# cd VirtualBox VMs/
root@jericho:/home/hipo/VirtualBox VMs# ls
Debian 6  Debian 9  Windows 10
root@jericho:/home/hipo/VirtualBox VMs# cd Debian 6/
r
oot@jericho:/home/hipo/VirtualBox VMs/Debian 6# ls
Debian 6.vbox  Debian 6.vbox-prev  Debian 6.vdi  Logs  NewVirtualDisk1.vdi  Snapshots

root@jericho:/home/hipo/VirtualBox VMs/Debian 6# VBoxManage modifyhd Debian 6.vdi –resize 20000
0%…10%…20%…30%…40%…50%…60%…70%…80%…90%…100%
root@jericho:/home/hipo/VirtualBox VMs/Debian 6#


 

Above command does resize the 10GB default created partition for Linux, where I have installed Linux which was 99% full of data, because of the many packages I installed to 20GB size, to make it bigger just use the respective size, be it 30000 (for 30GB) or 100000 (for 100GB) etc.

Even though in this example VBoxManage virtual partition resize command was done for GNU / Linux Operating System, it can be done for any other Operating as well to resize the size of the Virtual .VDI file (Virtual Machine) partition, be it Windows 7 / 8 / 10 or the rest of Free Operating systems FreeBSD / OpenBSD / BSD that are installed in a VM etc.

Next Launch the Virtual Machine with VBox Server client Program and install there Gparted (GNU Parted), as we'll need it to create a new Hard Disk Partition:

 

$ VirtualBox

 


Inside virtualmachine's in gnome-terminal / xterm etc. depending on the graphical environment used do install with apt-get:

 

debian:# apt-get install –yes gparted

 

debian~:# gparted


Notice that gparted has to be ran as a root superuser.

 

Run GParted and create new EXT3 filesystem that is 10GB (the size of the new created partition).

If you have installed Debian to place all partitions under / (root directory /dev/sda1) then the fresh new partition to create should be
/dev/sda3, anyways just look closely in EXT3 and in your case if the partiition is named differently create according to proper partition /dev/ naming.

I'll not run into details on how to create the partition with GParted as the program interface is very self-explanatory, the only thing is to apply the update to create partition and the ext3 filesystem, that's being done
with a green tick:

gparted-create-ext3-partition-howto-linux

Next step is to check with fdisk whether, we have ext3 properly created  filesystem as we've done already with GPARTED:

Once we have the partition created with EXT3 filesystem, we're ready to move /usr temporary to other folder, I use usually /root for the move but you can create anywhere a new folder for that and move to there.

To move to /root directory run again in terminal:

 

debian:~# mv /usr /root
debian:~# mkdir /usr

 

howto-extend-root-filesystem-disk-space-linux-move-usr-folder-to-root-temporary-debian-gnu-linux

 

Note that during the move operations, your Desktop icons will become without (with broken) pictures and the default Debian background picture is to disappear, that's because the GUI environment will soon realize /usr/ libraries that're periodically reloaded in memory are missing and will be unable to reload them as it does in a cycle.

That should take a few minutes, so grab a coffee or if you're a smoker (hope not as smoking kills 🙂 ), in 5 / 10 minutes time depending on your computer / server configuration, it will be over, so we're ready to create new /usr dir and mount the  new partition:

 

debian:~# mount /dev/sda3 /usr

 

howto-extend-root-filesystem-disk-space-linux-move-usr-folder-to-root-temporary-debian-gnu-linux1

 

Now we check with mount command whether mount is fine:

 

check-if-filesystem-is-properly-mounted-linux-debian-screenshot


Now  /dev/sda3 is mounted under /usr  and we have to move back /root/usr directory content back to the newly mounted /usr so we run command:
 

debian:~#  mv /root/usr/* /usr/*


Finally we need to create proper records for the new partition inside /etc/fstab (fstab –FileSystem Tab file – the file which describes instructs the Linux OS what partition to boot where, what)

HOW TO CHECK LINUX UUID FOR A PARTITION??

Before adding anything to /etc/fstab you need to check the UUID of /dev/sda3 (or whatever the partition is called), without proper UUID, the system might fail to boot.
So here is how to check the UUID we'll need for config:

 

hipo@debian:~$ /sbin/blkid /dev/sda3
/dev/sda3: UUID="2273db4b-3069-4f78-90fc-e7483c0305bd" SEC_TYPE="ext2" TYPE="ext3"

hipo@debian:~$ ls -al /dev/disk/by-uuid/
total 0
drwxr-xr-x 2 root root 100 Oct  6 05:16 .
drwxr-xr-x 6 root root 120 Oct  6 05:16 ..
lrwxrwxrwx 1 root root  10 Oct  6 05:16 2273db4b-3069-4f78-90fc-e7483c0305bd -> ../../sda3
lrwxrwxrwx 1 root root  10 Oct  6 05:16 b98d92cd-41aa-4e18-a474-9b8df445dbe5 -> ../../sda1
lrwxrwxrwx 1 root root  10 Oct  6 05:16 f27f7448-f200-4983-b54f-b9e5206f77ac -> ../../sda5

As you can see our /dev/sda3 UUID is 2273db4b-3069-4f78-90fc-e7483c0305bd

Further on lets view and edit /etc/fstab you can also download a copy of my Virtual Machine fstab here

 

debian:~# cat /etc/fstab

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=b98d92cd-41aa-4e18-a474-9b8df445dbe5 /               ext3    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=f27f7448-f200-4983-b54f-b9e5206f77ac none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/scd1       /media/cdrom1   udf,iso9660 user,noauto     0       0


We need to add following line to  /etc/fstab:
 

UUID=2273db4b-3069-4f78-90fc-e7483c0305bd    /usr        ext3 error=remount-ro    0    1

 


Open the file with your favourite text editor (gedit / nano / pico / vim / joe) etc.

debian:~# vim /etc/fstab

 

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=b98d92cd-41aa-4e18-a474-9b8df445dbe5 /               ext3    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=f27f7448-f200-4983-b54f-b9e5206f77ac none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/scd1       /media/cdrom1   udf,iso9660 user,noauto     0       0

UUID=2273db4b-3069-4f78-90fc-e7483c0305bd     /usr        ext3 error=remount-ro    0    1    

Basicly it should be possible to add (for historic reasons) also instead of UUID=2273db4b-3069-4f78-90fc-e7483c0305bd  /dev/sda3
So it looks like so but, the better practice is to use UUID line given.

Well that's all folks now /usr directory will contain all your heavy root partition (disk filling) libraries and files, so you can happily use /var/lib/mysql or /var/lib/postgresql /var/www to store your web application files and import your databases.

Big thanks to Ubuntu Forums article – How do I increase the hard disk size of the Virtual Machine article for inspiring this post.

Hope that helps anyone and thanks and other comments are always welcome ! 🙂

List and get rid of obsolete program core dump files and completely disable core files on FreeBSD

Tuesday, November 1st, 2011

My FreeBSD router has started running out of space, I looked for ways to clean up some space. So I remembered some programs are generating core files while they crash. Some of these files are really huge and ban be from 1Mb to > 1G.

I used find to first list all my produced core files starting from root directory (/) , like so:

find / -name core -exec du -hsc {} ;
....

Having a list of my core files with the respective core file size and after reviewing, I deleted one by one the cores which were there just taking up space.
It’s a wise idea that core dumps file generation on program crash is completely disabled, however I forgot to disable cores, so I had plenty of the cores – (crash files which are handy for debug purposes and fixing the bug that caused the crash).

Further on I used an /etc/rc.confdumpdev=NO , variable which instructs the kernel to not generate core files on program crash:

freebsd# echo 'dumpdev=NO' >> /etc/rc.conf

Next, to make dumpdev=NO , take affect I rebooted the server:

freebsd# shutdown -r now
...

There is a way to instruct every server running daemon to know about the newly set dumpdev=NO by restarting each of the services with their init scripts individually, but I was too lazy to do that.

How to debug mod_rewrite .htaccess problems with RewriteLog / Solve mod_rewrite broken redirects

Friday, September 30th, 2011

Its common thing that CMS systems and many developers custom .htaccess cause issues where websites depending on mod_rewrite fails to work properly. Most common issues are broken redirects or mod_rewrite rules, which behave differently among the different mod_rewrite versions which comes with different versions of Apache.

Everytime there are such problems its necessery that mod_rewrite’s RewriteLog functionality is used.
Even though the RewriteLog mod_rewrite config variable is well described on httpd.apache.org , I decided to drop a little post here as I’m pretty sure many novice admins might not know about RewriteLog config var and might benefit of this small article.
Enabling mod_rewrite requests logging of requests to the webserver and process via mod_rewrite rules is being done either via the specific website .htaccess (located in the site’s root directory) or via httpd.conf, apache2.conf etc. depending on the Linux / BSD linux distribution Apache config file naming is used.

To enable RewriteLog near the end of the Apache configuration file its necessery to place the variables in apache conf:

1. Edit RewriteLog and place following variables:

RewriteLogLevel 9
RewriteLog /var/log/rewrite.log

RewriteLogLevel does define the level of logging that should get logged in /var/log/rewrite.log
The higher the RewriteLogLevel number defined the more debugging related to mod_rewrite requests processing gets logged.
RewriteLogLevel 9 is actually the highest loglevel that can be. Setting the RewriteLogLevel to 0 will instruct mod_rewrite to stop logging. In many cases a RewriteLogLevel of 3 is also enough to debug most of the redirect issues, however I prefer to see more, so almost always I use RewriteLogLevel of 9.

2. Create /var/log/rewrite.log and set writtable permissions

a. Create /var/log/rewrite.log

freebsd# touch /var/log/rewrite.log

b. Set writtable permissons

Either chown the file to the user with which the Apache server is running, or chmod it to permissions of 777.

On FreeBSD, chown permissions to allow webserver to write in file, should be:

freebsd# chown www:www /var/log/rewrite.log

On Debian and alike distros:

debian:~# chown www-data:www-data /var/log/rewrite.log

On CentOS, Fedora etc.:

[root@centos ~]# chown httpd:httpd /var/log/rewrite.log

On any other distribution, you don’t want to bother to check the uid:gid, the permissions can be set with chmod 777, e.g.:

linux# chmod 777 /var/log/rewrite.log

Next after RewriteLog is in conf to make configs active the usual webserver restart is required.

To restart Apache On FreeBSD:

freebsd# /usr/local/etc/rc.d/apache2 restart
...

To restart Apache on Debian and derivatives:

debian:~# /etc/init.d/apache2 restart
...

On Fedora and derivive distros:

[root@fedora ~]# /etc/init.d/httpd restart
...

Its common error to forget to set proper permissions to /var/log/rewrite.log this has puzzled me many times, when enabling RewriteLog’s logging.

Another important note is when debugging for mod_rewrite is enabled, one forgets to disable logging and after a while if the /var/log partition is placed on a small partition or is on an old server with less space often the RewriteLog fills in the disk quickly and might create website downtimes. Hence always make sure RewriteLog is disabled after work rewrite debugging is no longer needed.

The way I use to disable it is by commenting it in conf like so:

#RewriteLogLevel 9
#RewriteLog /var/log/rewrite.log

Finally to check, what the mod_rewrite processor is doing on the fly its handy to use the well known tail -f

linux# tail -f /var/log/rewrite.log

A bunch of time in watching the requests, should be enough to point to the exact problem causing broken redirects or general website malfunction.
Cheers 😉

A quick and easy way to install Social Network on Linux/BSD System with Elgg

Monday, March 14th, 2011

elgg-blue-logo
I'm experimenting this days with Elgg – An Open Source Free Software GPLed Social Network which enables users to quickly create Communities.

Elgg is really easy to install and all it requires is a Linux/BSD or Windows system with PHP, MySQL and Apache installed.

Elgg is provided with dozens of nice plugins which for a short time enables individual to create fully operational Social Network like facebook.

Many people nowdays use facebook without realizing how bad facebook is how it breaks their privacy.
Facebook is actually a spy network, it stores data and pictures, likings and user behaviour of million of users around the world.
This needs to be stopped somehow, maybe if people start using the free software networks like elgg to build a mini-community which has profound interests in a certain spheres of work, life and amusement.
The evil empire of facebook will slowly start to loose it's position and the small projects networks based on Elgg and the other Free Software Social Networks which are currently available will start to rise up.
I'm currently really a novice into Elgg but I'm more convinced that the guys who develop it and contribute to it in terms of handy plugins have done really a great job.

It's ultra easy even for non professional middle level user to setup himself an Elgg install.
The installation procedure is not much harder than a simple wordpress blog or joomla based website install.
The installation of elgg takes no more than 10 to 20 minutes, the plugin installation and setup time further could take few days but in the end you have a full featured Social Network! This is really amazing.
The installation of new plugins in elgg is also fool proof / easy all you have to do to equip a newly installed elgg with plugins is to go to it's root directory and look for the mod directory. The new plugins which needs to be installed, could be directly downloaded and saved via links, elinks, lynx or even wget to the elgg installation directory.

Most of the elgg plugins comes in a form of zip files so after being installed simply executing:

server:/home/elgg/mysocialnetwork/mod# unzip walltowall.zip
....

The above cmd will for example unzip the WallToWall elgg plugin and the plugin will be further ready to be enabled via the administrator user set upped during your elgg installation.

The configurations of elgg are being accomplished via:

Administration -> Tool Administration

I should I'm still experimenting with Elgg social, until this very moment I've installed the following elgg plugins:

aaudio
akismet
artfolio
blog
bookmarks
buddytalk
captcha
categories
chat
crontrigger
custom_index
custom_profile_fields
default_widgets
diagnostics
elgg-ebuddy
embed
embedvideo
emoticons
externalpages
family
fbconnect
file
file_tree
flyers
forum
friend_request
friends
garbagecollector
groups
htmlawed
invitations
invitefriends
izap_videos
kaltura_video
lastfm
likes
logbrowser
logrotate
lucygames
members
messageboard
messages
milockergames_frameme
noscript_message
notifications
pages
polls
profile
reportedcontent
resume
river_comments
riverdashboard
riverfaces
search
siteaccess
tagcloud
theme_simpleneutral
thewire
tidypics
tidypicsExt
tinymce
twitter
twitterservice
user_contact_list
uservalidationbyemail
walltowall
weather
wp1
zaudio

One very handy feature I truly enjoy about Elgg is that it gives every user an own blog which or in other words when somebody registers in Elgg, he automatically gets a personal blog! How cool this is Yeash 😉
The Elgg photo upload plugin is also another interesting story. The photo plugin is a way better from my first impressions than facebook's buggy upload client.
Elgg also uses heavily jquery for it's various operations and the user experience feels very interactive.

Of course as with all free software things are not perfect some of the elgg plugins or (mods) as they are called are not working.
For example I couldn't make by so far the weather plugin which is supposed to report the weather.

Maybe some tweakening of the not working plugins will easily make them working. What is really important is that the Elgg basis system looks and seems to work really good and enpowers the user with a social network alternatives to the ugly facebook.

In order to experiment with Elgg and I've established a small social network targetting at University College and School Students called MockATeacher – mockateacher.com>/i>. The idea behind is to help students in their report writting by providing them with a place where they can meet other students and share files.

Some other aspects I've planned for MockATeacher is to build a small community of people who would like to share about idiot teachers, teacher stupid sayings as well as to mock the idiotic type of education that we and our children are up to in this age.
Just to close up, if you're looking for some time to spend in experimenting in an enjoyable way you definitely need to install elgg and play with it 😉

How to remove the meta generator Content (Joomla! – Copyright) in Joomla 1.5

Thursday, December 30th, 2010

Joomla-remove-meta-generator-content-to-hide-joomla-site-install
Do you wonder How to change <meta name="Generator" content="Joomla! – Copyright (C) 2005 – 2007 Open Source Matters. All rights reserved." /> in Joomla 1.5

If yes, Here is how I've just found to remove the:

 

in my Joomla installation.

I need to remove that as a part of making my website not to leak out that it runs on top of Joomla.

So here is how:

1. Go to your Joomla website main root directory
2. Edit /libraries/joomla/document/html/renderer/head.php
Look for line: 83 in the /libraries/joomla/document/html/renderer/head.php
There you will notice the code:

$strHtml .= $tab.'<meta name="generator" content="'.$document->getGenerator().'" />'.$lnEnd;

In order to remove the <meta name="generator" content="Joomla …." /> change the above code to something like:

$strHtml .= $tab.'<meta name="generator" content="My Custom Web site Generator name" />'.$lnEnd;

That's all now next time you refresh your website the content="Joomla! – Copyright (C) 2005 – 2009 Open Source Matters. All rights reserved." will be no more.
Cheers! 🙂