Weird LVM behavior

[Stefan Farrelly]

Looks like a serious connection problem with your EMC. Call EMC and get them to check their EMC frame for any errors. If you reboot your server and do an ioscan and dont get the volumes you expect then youve got a problem connecting to the EMC - or an EMC bin file problem.

[John Palmer]

It's definitely a problem with the EMC frame. All your data volumes appear to have been lost.

[Mike Smith_2]

That's the interesting part. I can reboot the machine all I want, the devices never are shown in ioscan or sam, but the machine comes up and uses those data volumes like nothing is wrong.

Those data volumes constitute a database, and it's working normally.

I suppose not only was this question of what's wrong, but also why does it work irregardless of what I see?

The /dev/dsk and /dev/rdsk files are there for the missing volumes. Is that and /etc/lvmtab all that's needed to make it work?

[Tim Malnati]

I'm in agreement that the problem probably resides within the EMC. I'm a bit curious about some other indications that you have not included in your post. The two in particular is the output from inq and the indications you are seeing in SymmConsole. Does inq see everything? Are mappings diplaying correctly? Any errors or other stange behavior coming up on the EMC side? Are these straight volumes or bcv's? Are you using powerpath? Is this K box just another server or does it have a different function than the rest of the rest of the machines?

I'm also a bit confused about the quantity of gatekeeper devices that are defined. Twelve devices for two interfaces just seems like a lot to me. I have to claim a little ignorance here; I don't know all the considerations involved, but EMC techs that I've worked with have not suggested creating gatekeepers like this.

I know this is more questions than answers but I'm trying to expand my knowledge here a little bit too. The problem that you are dealing with is very strange; totally different that other EMC issues that I've encountered.

[Tim Malnati]

Thanks for the response. I'm trying to do some learning here too.

This is bizarre! Inq is normal but ioscan is confused. And the machine boots, fsck's, and mounts everything like there is nothing wrong. Like I said, bizarre. Another curious thing is the 'Invalid argument' error message from vgscan. This may be normal with a vgscan error though, I don't see enough vgscan errors to know any better. I'm starting to suspect a possible error in ioscan processing (other than the obvious), but I really don't have much of a clue as to what this error could be caused from at this point. I'm assuming that things responded normally at some point in the past. Has anything changed since that point in time from a configuration or patch point of view?

I realize you have alternate paths to the gatekeepers. My confusion comes from EMC never suggesting more than two to me. I'm no EMC wiz kid, and I have no formal EMC training either. I'm just trying to grasp an understanding why so many more with only two scsi interfaces and twelve total partitions defined.

[Mike Smith_2]

The 12 total partitions aren't 12 at all. They're six, and they're the gatekeepers. INQ shows ALL the volumes, 12 data volumes, and 6 gatekeepers as seen by each SCSI interface.

It would be represented by having device files of both c0t1d2 and c4t1d2. These files are the same volume as seen by each interface.

All the machines get the 'invalid argument' after trying to do c5t2d0. It's the empty CDROM.

[Mike Smith_2]

The INQ vs. 'insert any HPUX tool here' conflict is really why I posted it here under 'LVM'. I'm not convinced it has much to do with the EMC. I could be wrong, but it just doesn't seem like it.

[John Palmer]

It sounds very much as if all the 'query' commands such as those used by ioscan and vgscan are not getting any response from the EMC.

Where LVM is specifically driving a SCSI device that it knows about then all is well.

I presume that commands like 'vgdisplay' and 'pvdisplay' are ok.

I'm no expert on EMC. Does it have any facility to stop hosts doing the sort of 'what's on this bus' query commands?

I still think that this is an EMC issue.