topic Re: Add LUN to RHEL qlogic single path in Operating System - Linux

Add LUN to RHEL qlogic single path

Hardydrewandthenancyboy — Mon, 15 Jun 2009 09:08:33 GMT

I have RHEL connected to MSA1000 via a qlogic card on /proc/scsi/qla2300/2

I want to add a new set of disks with the existing MSA and existing qlogic fibre adaptor.
I've set the disks up in SSP (Logical Disk 15) and I did the hp_rescan and can see the new LUN under cat /proc/scsi/qla2300/2:
Id:Lun) * - indicates lun is not registered with the OS.
0: 0): Total reqs 93193, Pending reqs 0, flags 0x0, 0:0:81,
0: 3): Total reqs -601584562, Pending reqs 2, flags 0x0, 0:0:81,
0: 4): Total reqs 998696771, Pending reqs 0, flags 0x0, 0:0:81,
0: 6): Total reqs -1692703972, Pending reqs 0, flags 0x0, 0:0:81,
0:15): Total reqs 0, Pending reqs 0, flags 0x0*, 0:0:81,

I've entered the command
echo "scsi add-single-device 2 0 0 15" > /proc/scsi/scsi

in order to get the OS to see the new LUN but its not showing up under cat /proc/scsi/scsi

Do I need a reboot of the system to add a new LUN? Anything else that I could do besides reboot? I would expect the star to disappear indicating the OS now recognises the new LUN?

Re: Add LUN to RHEL qlogic single path

John McNulty_2 — Mon, 15 Jun 2009 14:34:19 GMT

Hi. I have a vague memory that this didn't work very well on older Linux kernels. It's been tried before however and discussed here:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1245079591390+28353475&threadId=1170635

Perhaps you can try some of the suggestions from there. I no longer have access to a SAN attached RHEL 4 system to verify any of this.

John

Re: Add LUN to RHEL qlogic single path

Hardydrewandthenancyboy — Mon, 22 Jun 2009 07:13:31 GMT

I should have mentioned box is running esx server. This is where the problem was. I assumed it was same as RHEL but it's slightly different.
Maxluns esx setting was set to 6. When I increased to 16 (not 15!) the box registered the new luns fine. Thx

Re: Add LUN to RHEL qlogic single path

Hardydrewandthenancyboy — Mon, 22 Jun 2009 07:15:32 GMT

new lun now recognised. There was no need to do this at the o/s level as the box was running esx, it was resolvable at the esx web interface.