topic Re: lun number limit on emc disk array in Operating System - HP-UX

lun number limit on emc disk array

Francois LAURENT — Tue, 06 Jul 2004 10:36:27 GMT

Hi all,

I hope this question is not so stupid for this forum :
I have a rp5470 11.11 box with 2 a6795a FC cards linked to symetrix emc array. My patch level is phkl_27751 for fcmsutil and phkl_26743 for lvm.

I'm not able to see lun over 7 (i see only 8 lun). I know this limitation on scsi devices but i think in FC, this limitation reached 128.

in scsi, this limitation is due to VSA (Volume Set Addressing) but it's not tru for FC.

I'm only see 0-7 lun on one target, theres is no other target used.
What can i do to see others lun ?

Thanks for help

Regars
Francois

Re: lun number limit on emc disk array

Patrick Wallek — Tue, 06 Jul 2004 10:40:23 GMT

Can you post your 'ioscan -kfnC disk' output? I have always seen where (assuming LUN7 = c2t0d7) LUN 8 would be c2t1d0. Is this not happening?

Re: lun number limit on emc disk array

Jeff Schussele — Tue, 06 Jul 2004 10:50:10 GMT

Hi Francois,

As Patrick noted the device or "d" value cannot exceed 7 & the 9th LUN will increment the target or "t" value by 1.
The actual LUN limit per controller IS 128 believe (16 targets with 8 LUNS each). But I have setups where we have >128 LUNs & in those cases LUN 129 causes a controller "c" value incrementation. If your EMC storage admins zones them properly, you'll see them all.

Rgds,
Jeff

Re: lun number limit on emc disk array

Rita C Workman — Tue, 06 Jul 2004 10:53:21 GMT

Well...EMC sets up the luns via the binfile. You don't mention your Symm array model, but I'm going guess you are not creating the binfile.

When you add more disk, hence more luns, you can max out the box. But you can try to get EMC engineers to correct this. I ran into this on an older array that was sliced up in way to small of luns (hence it max'd). After a little friendly persuasion, the backline engineers finally got it so I could go past 0-7.
Call EMC....and have them correct the binfile to allow for the additional luns.

(And make sure on your next array, you slice things up larger, so you don't run into this when the box begins to fill up)..

Rgrds,
Rita

Re: lun number limit on emc disk array

Francois LAURENT — Fri, 16 Jul 2004 05:06:06 GMT

Hi all,

Sorry to not responding more rapidely, i was out off office.

You are all right, in fact, it was a setting emc problem. Re-mapping disk with good flags done what you tell : the devices are seen on a other target.

Thanks a lot for help.