A sample text widget

Etiam pulvinar consectetur dolor sed malesuada. Ut convallis euismod dolor nec pretium. Nunc ut tristique massa.

Nam sodales mi vitae dolor ullamcorper et vulputate enim accumsan. Morbi orci magna, tincidunt vitae molestie nec, molestie at mi. Nulla nulla lorem, suscipit in posuere in, interdum non magna.

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 grub loader. In order to resolve the problem, you need to boot up with recovery CD, and then you need to do the following […]

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, before that you can use NMAP command to verify whether port is open or close.

NMAP abbreviation is network mapper

NMAP is […]

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 sure HBA card instered properly, I had this problem with my Solaris box and after I have insereted the card properly, system detected […]

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 cache si so bi bo in cs us sy id wa 0 0 0 129277344 346144 2033648 0 0 0 4 0 0 0 0 […]

How to diffierenate from Local disks vs SAN

How to differentiate from Local disks vs SAN

Some times system admins get confused that disks are from SAN or local disk. Please check the following information and this server is connected to SAN. If you look line 3,4,5 and 6, those are connected to storage.

[root@saturn block]# ls -l /sys/block/*/device lrwxrwxrwx 1 root […]