[SOLVED] Best Prac Advice Sought: UUID-based labeling SAN-presented LUNS to RHEL4

SteveInTallyFL · 10-22-2009, 07:38 AM

I installed and initialized the IBM/LSI RDAC (mpp) drivers and then I had LUNs presented to my server from an IBM DS4300. I wanted to mount them with UUID-based labels. The mppBusRescan returned them as /dev/sd[a-c]. There were no mappings to /dev/disk/by-id even though there was a udev rule in 51-by-id.rules.

Quote:

(KERNEL="sd*[!0-9]", PROGRAM="/sbin/scsi_id", SYMLINK="disk/by-id/scsi-%c")

So I ended up using LVM to partition, format, and mount them. I have 2 concerns:

I have a nagging suspicion that LVM on top of SAN is unnecessary overhead to the I/O processing.
I don't know if LVM will handle a change in sd* assignment should a SAN-presented LUN be removed.

I have a 'gut feeling' that I must have missed something. Is there a better way?

ilikejam · 10-22-2009, 09:16 AM

Hi.

Had you formatted the LUNs before you looked for their UUIDs?

Dave

SteveInTallyFL · 10-23-2009, 07:14 AM

No, I had not. I looked for them before I went with the LVM approach to partitioning and formatting.

ilikejam · 10-23-2009, 10:38 AM

The UUIDs are a property of the filesystem, so the LUNs would have to be formatted before you'd see them.

Dave