Linux

Check Raid Controller on Linux and Monitor RAID

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How to check the raid controller on Linux: Monitoring Tools /proc/mdstat You should get to know /proc/mdstat, looking at it often. This will tell you the state of your arrays, and very importantly it will tell you whether any drives have failed, and whether any arrays are degraded. Check, and check regularly! xosview xosview is … Read more

Using SED in Linux to Edit Large Files

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Recently I encountered a server that had an Apache configuration file that was over 500,000 lines. Changes needed to make were to comment out the CustomLog line for each domain in /etc/httpd/httpd.conf. For this command, I used SED. NAME sed – stream editor for filtering and transforming text SYNOPSIS sed [OPTION]… {script-only-if-no-other-script} [input-file]… DESCRIPTION Sed … Read more

Linux mount CIFS Windows Share

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CIFS stands for Common Internet File System. This is application-level network protocol mainly used to provide shared access to files, printers, serial ports, and miscellaneous communications between nodes. You can access CIFS share from Linux and mount them as a regular filesystem. This is handy if there is a backup service like Infrascale where you … Read more

Show List Of Network Cards in Linux

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How do I display a list of all network cards under Linux operating systems? You can use any one of the following command to list network cards installed under Linux operating systems. Please note that the ifconfig and ip commands will also display interfaces information about vpn, loopback, and other configured interfaces. lspci command : … Read more

Log in with an SSH private key on Linux

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Using a text editor, create a file in which to store your private key. This example uses the file private_key.txt. To edit the file in nano, type the following command Paste the private key into the file. Be sure to include the BEGIN and END lines. Run the following command to change the file permissions … Read more

Disk I/O Stats in linux

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Sysstat

For disk I/O trending there are a few options. the sar command from sysstat. By default, it gives output like this:

# sar
Linux 2.6.32-642.11.1.el6.x86_64 (test.geekdecoder.com)    01/26/2017      _x86_64_        (2 CPU)

12:00:01 AM     CPU     %user     %nice   %system   %iowait    %steal     %idle
12:10:01 AM     all      0.03      0.00      0.03      0.09      0.00     99.85
12:20:01 AM     all      0.27      0.00      0.04      0.00      0.00     99.69
12:30:01 AM     all      0.33      0.00      0.05      0.00      0.00     99.62
12:40:01 AM     all      1.01      0.00      0.18      1.18      0.00     97.63
12:50:01 AM     all      0.15      0.00      0.04      0.00      0.00     99.80
01:00:01 AM     all      0.16      0.00      0.03      0.00      0.00     99.80
01:10:01 AM     all      0.22      0.00      0.04      0.00      0.00     99.74
01:20:01 AM     all      0.36      0.00      0.05      0.00      0.00     99.59
01:30:01 AM     all      0.23      0.00      0.04      0.00      0.00     99.74
01:40:01 AM     all      0.70      0.00      0.25      6.23      0.00     92.82
01:50:01 AM     all      0.13      0.00      0.03      0.00      0.00     99.83
02:00:01 AM     all      0.16      0.00      0.04      0.00      0.00     99.80
02:10:01 AM     all      0.21      0.00      0.04      0.00      0.00     99.75
02:20:01 AM     all      0.30      0.00      0.04      0.00      0.00     99.66
02:30:01 AM     all      0.14      0.00      0.03      0.00      0.00     99.83
02:40:01 AM     all      0.20      0.00      0.03      0.00      0.00     99.76
02:50:01 AM     all      0.32      0.00      0.05      0.00      0.00     99.63
03:00:01 AM     all      0.21      0.00      0.03      0.00      0.00     99.76
03:10:01 AM     all      0.19      0.00      0.04      0.00      0.00     99.77
03:20:01 AM     all      0.12      8.44      2.69     10.79      0.00     77.96
03:30:01 AM     all      0.13      4.52      8.36      0.30      0.00     86.69
03:40:01 AM     all      0.48      0.00      0.05      0.02      0.00     99.45
03:50:01 AM     all      0.15      0.00      0.04      0.01      0.00     99.80
04:00:01 AM     all      0.13      0.00      0.03      0.00      0.00     99.84
04:10:01 AM     all      0.48      0.00      0.06      0.04      0.00     99.43
04:20:01 AM     all      0.17      0.00      0.05      0.11      0.00     99.67
04:30:01 AM     all      0.22      0.00      0.04      0.00      0.00     99.74
04:40:01 AM     all      0.89      0.00      0.08      0.16      0.00     98.87
04:50:01 AM     all      0.55      0.00      0.07      0.05      0.00     99.34
05:00:01 AM     all      0.11      0.00      0.04      0.01      0.00     99.85
05:10:01 AM     all      0.09      0.00      0.03      0.00      0.00     99.87
05:20:01 AM     all      0.17      0.00      0.04      0.00      0.00     99.80
05:30:01 AM     all      0.27      0.00      0.05      0.08      0.00     99.60

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Find Out Hard Disk Specs on Linux

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Find your drives # fdisk -l Disk /dev/sda: 17.2 GB, 17179869184 bytes 255 heads, 63 sectors/track, 2088 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0007f474 Device Boot Start End Blocks Id System /dev/sda1 … Read more

Neighbor table overflow Error in Linux

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The ‘neighbor table overflow’ is a VERY common linux issue on large networks. Some network trigger this with default linux settings (because the previous network regime put so many IP address subnets on a single vlan , it creates large ARP tables – which is not normal / default settings). It is not an indication … Read more