topic Re: Scanning for luns presented to Linux box in Operating System - Linux

Scanning for luns presented to Linux box

Waqar Razi — Wed, 17 Jun 2009 14:41:09 GMT

I am an HPUX admin and in HPUX, we use ioscan command to scan for new LUNs presented to an HPUX system. How can I see the LUNS presented to a Linux box. Lets say, storage admin have presented some luns to linux bix, what are the steps to make them seen in linux (RHEL).

Re: Scanning for luns presented to Linux box

Ivan Ferreira — Wed, 17 Jun 2009 14:43:25 GMT

Please see this thread:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1060267

Re: Scanning for luns presented to Linux box

John McNulty_2 — Wed, 17 Jun 2009 15:21:50 GMT

What version of Redhat ?

Re: Scanning for luns presented to Linux box

Waqar Razi — Wed, 17 Jun 2009 15:41:31 GMT

REd hat enterprise 4

Re: Scanning for luns presented to Linux box

Tony Cicone — Wed, 17 Jun 2009 19:25:29 GMT

Attached script is recommended by HP for rescanning scsi bus.

Re: Scanning for luns presented to Linux box

Colin Topliss — Wed, 17 Jun 2009 21:43:13 GMT

I've found that sometimes you need to reboot the server before you can see the luns. Otherwise you can use the utils with the PSP (if you're brave enough to install it), or try rescanning the bus by (for example):

echo "scsi-qlascan" > /proc/scsi/qla2300/0
/bin/rescan-scsi-bus.sh

You might need to supply params to the rescan-scsi-bus.sh script - might depend on your hardware. You also have to have the rescan script :-)

To scan all channels, targets and LUNs, you could also try:

echo "- - -" > /sys/class/scsi_host/host0/scan

Not sure if this works with FC attached LUNs - I had a weird error on the test system, but our EVA has been behaving strangely over the past few days :-(

Once the LUNs can be seen, then Linux does the rest. You should be able to fdisk them, pvcreate them, or do whatever you want. xpinfo or evainfo (depending on what you have) will show you which devices you now have mapped.

Re: Scanning for luns presented to Linux box

Emil Velez — Wed, 17 Jun 2009 23:37:04 GMT

try
# hwinfo

its on suse by default i know of and as another HPUX guy it seems to be somewhat equivilent.

I also use

# lvmdiskscan

Re: Scanning for luns presented to Linux box

Fayez — Thu, 18 Jun 2009 05:07:54 GMT

Hi,

As Colin said, most time you have to restart the server after presenting new luns to the linux.

Re: Scanning for luns presented to Linux box

SJO EGGER — Thu, 18 Jun 2009 10:38:31 GMT

echo "- - -" > /sys/class/scsi_host/hostX/scan

this way works really fine and i make the same one in my scripts. make sure you do this for every HBA on your system.

no problem on SLES9/10/11.

roland