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Storage Knowledge for Unix/Linux System Administrator
Storage Knowledge for Unix/Linux System Administrator As a Unix/Linux system administrator you need to deal with SAN storage and here are some of the functionalities. 1. New SAN storage request…
change open files limit in linux
How to change open files limit in linux You can change the open file limits for individual users using the following method. You might want to also set in /etc/security/limits.conf…
Linux server is not booting and going to grub prompt
Linux server is not booting and going to grub prompt Some times when you boot the server it goes to grub prompt, you can assume there is a problem with…
How to rescan Fiber Channel and SCSI storage
You can force a rescan for SCSI drives like this: echo “- – -” >/sys/class/scsi_host/host Same for FiberChannel: echo “1″ >/sys/class/fc_host/host Also, you can reboot the system to Rescan.
NMAP command (How to check whether port is open or close)
NMAP command to check whether port is open or close Most of the time when there is a problem connecting to any specific port we use telnet command to verify,…
HBA card troubleshooting
HBA card troubleshooting HBA card is configuration is very important and if you can’t configure HBA card, then system won’t see your storage and you will have big issues. Make…
vmstats explanation
vmstat is one of the popular tool to analyze the Linux / UNIX server performance. # vmstat 1 5 procs ———–memory———- —swap– —–io—- –system– —-cpu—- r b swpd free buff …
Linux memory usage calculation
Linux memory usage calculation Most of the people get confuse about Linux memory usage. When you looked at used cloum, it says 3535 M, it doesn’t mean that system is…
How to mount loop device on Linux
Mounting loop device on Linux If you have ISO image, you can read ISO image by mounting it as loop device. mount -o loop boot.iso /mnt/bootimage/ It is very useful…
How to find BIOS version in Linux Servers
BIOS version in Linux Servers Some times very important to know what version of BIOS running, specially when we replace hardware on systems. # dmidecode | grep -i bios SMBIOS…