Some SAN LUNs not visible with RHEL 5.3

[Michal Ludvig]

Michal Ludvig wrote:
> Hi all,
> 
> I've got RHEL5.3 (x86) server with dual-port QLA2342 HBA (kernel module
> qla2xx) connected using FibreChannel to HP VA7410 disk array, one HBA
> port to each of the two SAN controllers.
> [...]
> However when I modprobe qla2xxx only LUN0 and LUN1 are attached as disks
> (sd). LUN2 is attached as 'scsi' and not accessible as a disk. The
> system knows that it exists, because there is an entry in
> /sys/class/scsi_device/ but is no accessible as a block device.

Just for the record - I had to enable "Secondary Path Presentation" from
the SAN console:

---
va7410> mgr -?

Usage:
[...]
mgr -ds {on | off}
-ds: Set Disable Secondary Path Presentation
[...]

va7410> mgr -ds off
---

(ehm, "off" means disable disable, ie enable secondary path
presentation, funny, isn't it? ;-)

Now rescan the LUNs and all is in place as it should be.

Michal