Posts Tagged ‘dedicated servers’

Linux: How to see / change supported network bandwidth of NIC interface and get various eth network statistics with ethtool

Monday, January 19th, 2015

linux-how-to-see-change-supported-network-bandwidth-of-NIC-interface-and-view-network-statistics
If you're a novice Linux sysadmin and inherited some dedicated servers without any documentation and hence on of the first things you have to do to start a new server documentation is to check the supported TCP/IP network speed of servers Network (ethernet) Interfaces. On Linux this is very easy task to verify the speed of LAN card supported Local / Internet traffic install ethtool (if not already preseont on the servers) – assuming you're dealing with Debian / Ubuntu Linux servers.

1. Install ethtool on Deb and RPM based distros

dedi-server1:~# apt-cache show ethtool|grep -i desc -A 3
Description: display or change Ethernet device settings
 ethtool can be used to query and change settings such as speed, auto-
 negotiation and checksum offload on many network devices, especially
 Ethernet devices.

dedi-server1:~# apt-get install –yes ethtool
..

ethtool should be installed by default on CentOS / Fedora / RHEL and  syntax is same like on Debs. If you happen to miss ethtool on any (SuSE) / RedHat / RPM based distro install it with yum

[root@centos:~] # yum -y install ethtool


2. Get ethernet configurations

To check the current eth0 / eth1 / ethX network (Speed / Duplex) and other network related configuration configuration:
 

dedi-server5:~# ethtool eth0

Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full

        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Speed: 1000Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        MDI-X: off
        Supports Wake-on: pumbag
        Wake-on: g
        Current message level: 0x00000001 (1)
        Link detected: yes

Having a NIC configured to act as Duplex is very important as Duplex communication enables LAN card to communicate both sides (Sent / Receive) packets simultaneously.

full-duplex-half-duplex-explained-picture

Probably most interesting parameters for most admins are the ones that are telling whether the NIC UpLink is 10megabyte / 100 megabyte or 1Gigabyte as well as supported Receive / Send ( Transfer ) speeds of LAN, a common useful ethtool admin use to just show current LAN ethernet interface speed:

server-admin1:~# ethtool eth0 |grep -i speed
        Speed: 1000Mb/s

 

To get info about NIC (kernel module / driver) used with ethtool:

dedi-server3:~# ethtool -i eth0 driver: e1000e
version: 1.2.20-k2
firmware-version: 1.8-0
bus-info: 0000:06:00.0

3. Make LAN Card blink to recognize eth is mapped to which Physical LAN

Besides that ethtool has many other useful use cases, for example if you have a server with 5 lan or more LAN cards, but you're not sure to which of all different EthX interfaces correspond, a very useful thing is to make eth0, eth1, eth2, eth3, etc. blink for 5 seconds in order to identify which static IP is binded physically to which NIC , here is how:

ethtool -p eth0 5


Then you can follow the procedure for any interface on the server and map them with a sticker 🙂

Ethtool is also useful for getting "deep" (thorough) statistics on Server LAN cards, this could be useful to identify sometimes hard to determine broadcast flood attacks:
 

4. Get network statistics with ethtool for interfaces
 

dedi-server5:~# ethtool -S eth0|grep -vw 0
NIC statistics:
     rx_packets: 6196644448
     tx_packets: 7197385158
     rx_bytes: 2038559235701
     tx_bytes: 8281206569250
     rx_broadcast: 357508947
     tx_broadcast: 172
     rx_multicast: 34731963
     tx_multicast: 20
     rx_errors: 115
     multicast: 34731963
     rx_length_errors: 115
     rx_no_buffer_count: 26391
     rx_missed_errors: 10059
     tx_timeout_count: 3
     tx_restart_queue: 2590
     rx_short_length_errors: 115
     tx_tcp_seg_good: 964136993
     rx_long_byte_count: 2038559235701
     rx_csum_offload_good: 5824813965
     rx_csum_offload_errors: 42186
     rx_smbus: 383640020

5. Turn on Auto Negotiation and change NIC set speed to 10 / 100 / 1000 Mb/s

Auto-negotiation is important as an ethernet procedure by which two communication devices (2 network cards) choose common transmission parameters such as speed, duplex mode, and flow control in order to achieve maximum transmission speed over the network. On 1000BASE-T basednetworks the standard is a mandatory. There is also backward compatability for older 10BASE-T Networks.

a) To raise up NIC to use 1000 Mb/s in case if the bandwidth was raised to 1Gb/s but NIC settings were not changed:

dedi-server1:~# ethtool -s eth0 speed 1000 duplex half autoneg off


b) In case if LAN speed has to be reduced for some weird reason to 10 / 100Mb/s

 

dedi-server1:~# ethtool -s eth0 speed 10 duplex half autoneg off

dedi-server1:~# ethtool -s eth0 speed 100 duplex half autoneg off

c) To enable disable NIC Autonegotiation:

dedi-server1:~# ethtool -s eth0 autoneg on


6. Change Speed / Duplex settings to load on boot

a) Set Network to Duplex on Fedora / CentOS etc.

Quickest way to do it is of course to use /etc/rc.local. If you want to do it following distribution logic on CentOS / RHEL Linux:

Add to /etc/sysconfig/network-scripts/ifcfg-eth0

vim /etc/sysconfig/network/-scripts/ifcfg-eth0

ETHTOOL_OPTS="speed 1000 duplex full autoneg off"

To load the new settings restart networking (be careful to have physical access to server if something goes wrong 🙂 )

service network restart

b) Change network speed / duplex setting on Debian / Ubuntu Linux

Add at the end of /etc/network/interfaces

vim /etc/network/interfaces

post-up ethtool -s eth0 speed 100 duplex full autoneg off

7. Tune NIC ring buffers

dedi-server1:~# ethtool -g eth0

Ring parameters for eth0:
Pre-set maximums:
RX:             4096
RX Mini:        0
RX Jumbo:       0
TX:             4096
Current hardware settings:
RX:             256
RX Mini:        0
RX Jumbo:       0
TX:             256

As you can see the default setting of RX (receive) buffer size is low 256 and on busy servers with high traffic loads, depending on the hardware NIC vendor this RX buffer size varies.
Through increasing the Rx/Tx ring buffer size , you can decrease the probability of discarding packets in the NIC during a scheduling delay.
A change in rx buffer ring requires NIC restart so (be careful not to loose connection to remote server), be sure to have iLO access to it.

Here is how to raise Rx ring buffer size 4 times from default value:

ethtool -G eth0 rx 4096 tx 4069

Get Hardware System info on Debian Linux / How to detecting hardware and servers model on GNU / Linux

Wednesday, December 12th, 2012

hardware-info-getting-on-linux-howto

Users who are novice to Linux should be probably interested on how to get a decent Hardware System Information. Getting system info on Windows is quite straight forward, however on Linux and especially on Linux servers it is a bit confusing at first and even for people who spend years administrating Linux servers, or even have a Linux desktop it is very likely after a period of time to forget how exactly last time got the hardware system information. I'm administrating Linux servers and running a linux desktop for already almost 11 years and often it happened I'm away from configuring a new server for a year, or even when configuring a new server I don't need to get exact system information from command line, as I know it already from the server hardware manual. However whether managing a bunch of dedicated servers or purchasing new systems which are physically away and someone pre-configured the server with some basis Linux install, often a very raw info is provided by the Dedicated Provider on exact server metrics. Other situation, where it is good idea to have a precise system hardware vendor information on a server, is if you just joined a company with a bunch of existing dedicated servers, whose exact hardware configuration is no documented anywhere and suddenly some RAID or piece of hardware located on 1 of the 100 dedicated servers starts misbehaving causing hour down-times and client important data loss.

In any of those cases it always takes me few times of research to find out what exact methodology I used to get the hardware info last time. To make my life for future times easier and not loose the few minutes of research and reading on how to get Linux server system information I decided to write this short article, which might hopefully be useful to others out there who face similar periodic questioning on what was the command to get hardware system info.

Of course the general commands to get some general overview on a Linux server as anyone knows are:

a. dmesg
b. cat /proc/cpuinfo
c. lspci
d. lsusb
c. free -m

A note to make here is that in order to have lsusb and lspci commands present you will have to have installed the deb packs lsusb and pciutils.

However as I prior said, this tools output is not enough or the output is not enough systematic and hard to read and understand especially for lazy or short memory admins like me. Thus it is worthy to mention few others which can be installed as a separate packages and gives more structured and very precised information on what kind of machine hardware you're accessing through ssh.

Here is the list of all of profiled hardware detection progs and scripts:

1. dmidecode

2. lshw

3. x86info

4. hwinfo

5. hardinfo

6. biosdecode

 

To install all of them in a raw with apt-get do:

debian:~# apt-get install --yes dmidecode lshw x86info hwinfo hardinfo superiotool
Reading package lists... Done
Building dependency tree      
Reading state information... Done
dmidecode is already the newest version.
hardinfo is already the newest version.
lshw is already the newest version.
The following extra packages will be installed:
  libhd16
The following NEW packages will be installed:
  hwinfo libhd16 superiotool x86info
0 upgraded, 4 newly installed, 0 to remove and 9 not upgraded.
Need to get 827 kB of archives.
After this operation, 4,506 kB of additional disk space will be used.
Get:1 http://ftp.uk.debian.org/debian/ squeeze/main libhd16 amd64 16.0-2 [696 kB]
Get:2 http://ftp.uk.debian.org/debian/ squeeze/main hwinfo amd64 16.0-2 [46.6 kB]
Get:3 http://ftp.uk.debian.org/debian/ squeeze/main superiotool amd64 0.0+r5050-1 [43.0 kB]
Get:4 http://ftp.uk.debian.org/debian/ squeeze/main x86info amd64 1.25-1 [40.9 kB]
Fetched 827 kB in 2s (378 kB/s)  
Selecting previously deselected package libhd16.
(Reading database ... 85783 files and directories currently installed.)
Unpacking libhd16 (from .../libhd16_16.0-2_amd64.deb) ...
Selecting previously deselected package hwinfo.
Unpacking hwinfo (from .../hwinfo_16.0-2_amd64.deb) ...
Selecting previously deselected package superiotool.
Unpacking superiotool (from .../superiotool_0.0+r5050-1_amd64.deb) ...
Selecting previously deselected package x86info.
Unpacking x86info (from .../x86info_1.25-1_amd64.deb) ...
Processing triggers for man-db ...
Setting up libhd16 (16.0-2) ...
Setting up hwinfo (16.0-2) ...
Setting up superiotool (0.0+r5050-1) ...
Setting up x86info (1.25-1) ...

Next just try to launch the tools one by one and check the content of the output, in my view  the most useful one and maybe also the most popular is dmidecode, the rest however might be useful to get specific hardware debug info.

1.  hwinfo

debian:~# hwinfo |tee -a server-hardware-info.txt
....

hwinfo will provide you a very long list of very thoroughful information on hardware. A lot of the info it shows however is not so useful for regular admins, but will be of high value to people who need to develop a new Linux driver for respective hardware.

2. lswh

debian:~# lshw > linux-hw-info.txt

lshw provides long list of debug information and if the output is not redirected to a file the screen gets flooded, if not piped to less. For that reason I will not paste output here.

3. x86info

debian:~# x86info

x86info v1.25.  Dave Jones 2001-2009
Feedback to <davej@redhat.com>.

Found 2 CPUs
————————————————————————–
CPU #1

EFamily: 0 EModel: 2 Family: 6 Model: 42 Stepping: 7
CPU Model: Unknown model.
Processor name string: Intel(R) Pentium(R) CPU G630 @ 2.70GHz
Type: 0 (Original OEM)    Brand: 0 (Unsupported)
Number of cores per physical package=8
Number of logical processors per socket=16
Number of logical processors per core=2
APIC ID: 0x0    Package: 0  Core: 0   SMT ID 0
————————————————————————–
CPU #2
EFamily: 0 EModel: 2 Family: 6 Model: 42 Stepping: 7
CPU Model: Unknown model.
Processor name string: Intel(R) Pentium(R) CPU G630 @ 2.70GHz
Type: 0 (Original OEM)    Brand: 0 (Unsupported)
Number of cores per physical package=8
Number of logical processors per socket=16
Number of logical processors per core=2
APIC ID: 0x2    Package: 0  Core: 0   SMT ID 2
————————————————————————–
WARNING: Detected SMP, but unable to access cpuid driver.
Used Uniprocessor CPU routines. Results inaccurate.

As you see x86info, mainly provides information on CPU Cache, exact model, family AND APIC (don't mix it with ACPI – advanced power management interface)
APIC is a chip that remaps IOs and IRQs of your computer to the CPU(s), thus in most cases it is more of not so needed debug information.

4. biosdecode

debian:~#  biosdecode
# biosdecode 2.9
ACPI 2.0 present.
    OEM Identifier: LENOVO
    RSD Table 32-bit Address: 0xBCD9C028
    XSD Table 64-bit Address: 0x00000000BCD9C068
SMBIOS 2.6 present.
    Structure Table Length: 2233 bytes
    Structure Table Address: 0x000EBB70
    Number Of Structures: 59
    Maximum Structure Size: 184 bytes
PNP BIOS 1.0 present.
    Event Notification: Not Supported
    Real Mode 16-bit Code Address: F000:BC66
    Real Mode 16-bit Data Address: F000:0000
    16-bit Protected Mode Code Address: 0x000FBC8E
    16-bit Protected Mode Data Address: 0x000F0000
PCI Interrupt Routing 1.0 present.
    Router ID: 00:1f.0
    Exclusive IRQs: None
    Compatible Router: 8086:27b8
    Slot Entry 1: ID 00:1f, on-board
    Slot Entry 2: ID 00:1b, on-board
    Slot Entry 3: ID 00:16, on-board
    Slot Entry 4: ID 00:1c, on-board
    Slot Entry 5: ID 02:00, slot number 21
    Slot Entry 6: ID 00:01, on-board
    Slot Entry 7: ID 00:06, on-board
    Slot Entry 8: ID 00:1d, on-board
    Slot Entry 9: ID 00:1a, on-board
    Slot Entry 10: ID 03:00, on-board
    Slot Entry 11: ID 00:02, on-board
    Slot Entry 12: ID 00:00, on-board

As you see biosdecode, also provides a lot of hex addresses, also reports on the exact CPU architecture on the system.

The line   XSD Table 64-bit Address: 0x00000000BCD9C068, indicated the host is running a 64 bit CPU, most of the rest info like Slot entries IDs etc. is not so useful.

The most useful info that biosdecode provides is the exact type of BIOS (Basic Input Output System) bundled with the system in my case the BIOS is running on a Lenovo host and is vendored by Lenovo, thus it shows in the cmd output:

OEM Identifier: LENOVO

5. hardinfo

debian:~# hardinfo | tee -a hardware-info.txt


hardinfo gnome screenshot debian  gnu / linux

HardInfo is the GNOME GTK+ program which displays robust and thouroughful info in same was as Windows System Info does on  GNOME Desktop. If however you run it under console or via ssh it does display what it detects as: 

Computer hardware, operating system, kernel modules, supported system languages, existing filesystems, Display, set environment variables, Existing system users, Processor type, Memory, PCI and USB devices, Printers (if attached), Battery type (if run on laptop), Storage, Other Input devices

hardinfo, does a few benchmarking tests using CPU stress test algorithms to do Blowfish encryption, CryptoHash, Fibonacci, N-Queens, FPU FFT and FPU raytracing. This benchmark values, if run on a couple of hosts can be used to compare different hardware performances.

6. dmidecode

debian: # dmidecode > system-hware-info.txt

The output from dmidecode is very very detailed and verbose. Though along with the useful info there is plenty of debug information, the debug information it provides is much user friendly / user comprehensible than the rest of tools, thus I guess dmidecode is nowadays preferred by me and probably most of the Linux sys admins.

debian:~# dmidecode |head -n 34
# dmidecode 2.9
SMBIOS 2.6 present.
59 structures occupying 2233 bytes.
Table at 0x000EBB70.

Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
    Vendor: LENOVO
    Version: 9QKT37AUS
    Release Date: 02/14/2012
    Address: 0xF0000
    Runtime Size: 64 kB
    ROM Size: 2560 kB
    Characteristics:
        PCI is supported
        BIOS is upgradeable
        BIOS shadowing is allowed
        Boot from CD is supported
        Selectable boot is supported
        BIOS ROM is socketed
        EDD is supported
        5.25"/1.2 MB floppy services are supported (int 13h)
        3.5"/720 KB floppy services are supported (int 13h)
        3.5"/2.88 MB floppy services are supported (int 13h)
        Print screen service is supported (int 5h)
        8042 keyboard services are supported (int 9h)
        Serial services are supported (int 14h)
        Printer services are supported (int 17h)
        ACPI is supported
        USB legacy is supported
        BIOS boot specification is supported
        Targeted content distribution is supported
    BIOS Revision: 0.37
 

Though it is the most useful tool on some hardware configurations it might not display any data because the BIOS is lacking a DMI implementation.

In almost all cases dmidecode is enough to check what kind of hardware you have ssh-ed to. dmidecode is available also not only on Debian but on Fedora and almost all (if not all Linux distros), through default repositories.