pvmove woes

[Patrick Wallek]

HP9000 T500
HP-UX 10.20

I am attempting to move ALL the data off of a drive that is threatening to go bad so I can replace it and not have to do a massive restore. The drive is NOT part of a mirror, darn it!!!!

I have been doing pvmove's to move all of the data off of this drive to other drives in this VG. I have run into a problem.

I tried to move all extents (732) off of this drive to another drive that has 1003 free extents, according to pvdisplay. When I tried to do this I got the error "pvmove: Not enough space".

Prior to this it let me move 615 extents off of this drive to another drive that had 837 extents free.

Anyone have any ideas on this? I'm totally confused.

Thanks!
Patrick

[James R. Ferguson]

Hi Patrick:

I suspect that your allocation policies are preventing the move.

...JRF...

[Patrick Wallek]

All but 1 of the LVs are set up as PVG-Strict and Distributed (created with -D y) and NOT striped. It has let me move all of the others from one disk to another, but they were all less than 100 extents as well.

I would think that since it let me move the others, it should let me move the problematic one as well.

[James R. Ferguson · Accepted solution]

Hi Patrick:

How about turning off the distributed allocation with 'lvchange' and then trying the 'pvmove'?

...JRF...

[Patrick Wallek]

Your suggestion sent me in the right direction James. I did turn off the Distributed option, but I also had to turn off PVG-Strict. That doesn't make sense to me, but when I did, it started working.

I was trying to figure out how to turn off the Distributed option, I just couldn't remember the lvchange command.

Thanks again!

[James R. Ferguson]

Hi Patrick:

I'm happy I could help. Hopefully all is now safely moved off your failing disk.

The man pages for 'lvchange' note that "The distributed allocation policy REQUIRES the PVG-strict allocation policy (-s g) to ensure that mirrors of distributed extents do not overlap...". I can only assume, therefore, that LVM was being "proactive" in the event that you WOULD mirror later.

Regards!

...JRF...

[Patrick Wallek]

James,

You could be right. I knew -D required -s g, but I'm still confused as to why it wouldn't let me move the stuff with PVG-strict. It's all in the same PVG so why not let it move it. Oh well.

All is not moved yet, but it is well on its way now.

I guess the next challenge is going to be figuring out how to rebalance the disks once I get the failing one replaced.

Fortunately it is a test system and the data is test data, so if it is a bit slower it won't matter much. I would just like to avoid copying 180GB of data from my production server or restoring that much over the network.