time it takes to activate VG during boot

[Sean OB_1]

Howdy,

Has anyone seen any significantly longer times to activate a VG containing vxfs file systems based upon how large the VG is?

I have a client who states that it takes much longer to boot a system with one "large" lun (100gb) than an otherwise identical system with 25x5gb vg's.

Has anyone else witnessed anything similar?

[Devender Khatana]

Hi,

Filesystem size will not cause this problem untill it was closed badly & system needs to run fsck on it. There must be some othe reasons like additional startup scripts or different hardwares. This could be due to fastboot setting also which could have been disabled in one & enabled in other.

We have servers with around 40 file systems of different sizes ranging from 10GB to 1.5TB & mount time for all is same.

HTH,
Devender

[Sean OB_1]

These are vpars in an 8400 and are configured identically including fastboot. This much I've verified myself on a previous visit.

The customer claims that she watches from the console and it is on the step that activates the vg's where the delay happens.

She's a very competent admin so I doubt that she would confuse the step, or forget about fsck times on a bad shutdown.

I believe the only other difference is that the large luns come from an EMC symmetrix and the small luns come from a clariion.

[Devender Khatana]

Hi,

Yes Sean, The reason is the storage only. I am not experienced on EMC products but we have XP512 & XP1024 installed & there is a lot of difference in the time that system takes to detect the arrays. In XP512 it is around 3-4 minutes & Xp1024 does it within a minute or so.

But for XP it is done prior to file system mounts itself & after detecting the array prior to running startup scripts it flashes a message

NOTICE: vxvm:vxdmp: added disk array 7E7C, datype = XP512

Or

NOTICE: vxvm:vxdmp: added disk array 40394, datype = XP1024

Another difference here is that we use VxVm.

Could you put a script for activating this VG's after OS startup alongwith application startup or alongwith application startup script if there is one.
Moreover you can confirm this by try to activate and mount file system manually after OS start up & I am sure you will find no difference in time there.

HTH,
Devender

[Devender Khatana]

Sean,

I was just curious to know wheather you followed these & were able to conclude something?

Regards,
Devender

[Sean OB_1]

I have not had a chance to follow up on this with the client, but I will post my results when we are able to do some testing.

[Mel Burslan]

Sean,

This may be a bit of a late reply but if I were your client at this point I would like to get the link quality on the fiberoptic cabling between the server and the SAN checked from end to end. Mounting of a filesystem may be delayed due to an abrupt shutdown requiring fsck and whatnot, but a vgchange should not take more than few seconds at best or this is my experience so far. Unless of course something more sinister going on, like a bad link or god forbid a bad controller or something. Especially on the EMC side.

[Mark Fisher_4]

I would log a call with EMC. I have been battleing this issue since last May. VG activation for EMC luns via powerpath on dx500/dx700 take 80 to 200 seconds. EMC came out with a patch, Powerpath 4.3.1.2 , but it did not resolve it for me.

The more people who log tickets with EMC, it will put more heat on them to fix this.