pvmove to migrate lvols from one VG to another

[dgangemi]

Hi

I need to move some SAP-specific lvols in VG00 from local disk onto SAN. I don't want to go through the rigamarole of having to Put a SAN LUN into VG00, do the pvmove and then split the SAN LUN out of vg00 into it's own VG. I was wondering if I could do this:
pvmove /dev/vg00/lvol## /dev/disk/disk##
where disk## is actually a member of a different VG, say vg01.

I have a second question somewhat related, that I need to have an answer to for planning purposes: On a brand new rx2660; about how long does it take to move an lvol of say 30 GB from one disk to another?

TIA

[Court Campbell]

Sorry has to be same vg.

[Torsten.]

Hi,

did you read the man page?

It says:

"...
The pvmove command moves allocated physical extents and the data they contain from a source physical volume, source_pv_path, to one or more other physical volumes in the same volume group..."

and later:
"dest_pv_path The block device path name of a physical volume. It cannot be the source physical volume. It must be in the same volume group as source_pv_path."

Notice:
in the same volume group!


Consider to take a backup of your data, create a new VG, new LVOL and restore.

[A. Clay Stephenson]

Pvmove only works within a VG so choose a different plan.


The answer to your second question is "it depends". How busy is your system otherwise? What are the destination and source devices? ... but, for your purposes, a few tens of minutes is probably close enough. The fastest move will be a raw copy using dd with a bs=256k or a little bigger but this should be done with the filesystem unmounted.

[dgangemi]

I guess I was kind of in denial but I thought I'd get a confirmation. I guess I'll just have to do a file system copy for that particular box. Fortunately, on the other boxes, the lvols are already in the proper VG.

As to the second question, they aren't in production yet, so there's no load on them at all, and I'll definately have them in a maintenance window for this. Heance the need for a time estimate so I can request the appropriate amout of time.

[Tim Nelson]

Time..

Depends on the type of disk but from an interal disk to a properly configured array device 10-15 minutes.

Disclaimer:
Many assumptions here. ( array has good amount of cache, the lun is 0+1 vs Raid5, there are not a million other things going on, etc )

[dgangemi]

Thanks all