topic LUN 0 on va7400 in Disk Enclosures

LUN 0 on va7400

Randy Tarrier — Tue, 28 Jan 2003 19:53:15 GMT

I've run into a problem on my va7400 with a "phantom lun 0" that sounds similar to an earlier thread on Nikes w/version 11.0.0;
(http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xc7e4a848deccd61190050090279cd0f9,00.html)
but I'd like to be sure before I put this system into production.
I'm running an rp8400 hard partitioned into 2 hosts (11i) connecting to the va7400 via 2 brocade switches. Everything is redundant, hdw paths, controllers, etc. When I first started creating luns, there were none, and I created a 10mb lun 0 (fooling around). I later combined this lun w/100 gb lun into a single volume group; I put both paths into the same pvg.
I decided to get rid of the 10mb lun, so I used SAM to remove lvol's, vg's, then armcfg -L 0 -d . OOPs, forgot the pvremove, but I had already rm'd the device files. I repeated this process for lun 1 (which had been combined w/lun 0).
When I run an ioscan -fnC disk, both paths show up with "NO HDW". Armdsp -L shows no lun 0. Same when I reboot; on both systems. I also recreated a 100gb lun 1; when I ran insf -C disk, it created device files for both hdw paths. So now, in sam, I get this msg: /opt/sanmgr/commandview/client/sbin/armdsp, did not
provide a Serial Number for device file /dev/dsk/c6t0d0. (It can't find the lun).

What has me concerned: Before I created the first lun, ioscans never showed lun 0. The prior thread mentions this problem w/hpux 11.0.0 on Nike arrays, but no mention of this os or platform. I've searched quite a few threads looking for this situation.
Any ideas?

Re: LUN 0 on va7400

Eugeny Brychkov — Tue, 28 Jan 2003 20:06:29 GMT

For VA management software to function correctly you have to create LUN 0. Recommendations are to have its size = 10mb, security permission = 'WC' and no user data on it.
If you do not create LUN 0 then array automatically creates phantom LUN to allow server to access all other (may be) existing LUNs on the same virtual SCSI bus.
If you can not create LUN 0 using arm* command now, please use serial connection to VFP (virtual front panel, serial ports at the back of VA, use one of them)
Eugeny

Re: LUN 0 on va7400

Khalid A. Al-Tayaran — Tue, 28 Jan 2003 20:06:31 GMT

Hi,

I create and delete LUNs and VGs using the VA'a commands. Logical volumes are created in SAM. No problems so far.

Re: LUN 0 on va7400

Randy Tarrier — Tue, 28 Jan 2003 20:14:39 GMT

So I was living right up until I put the first lun 0 in a vg. Live and learn.I recreated it at 10mb, and it can collect dust. Thanks for the responses!