vgmove

[seastar]

Moving luns from one SAN to another and thinking to use vgmove and have a few questions...

Any issue with vgmove and vg00 - do I need any downtime or can that be done online?

Can I use vgmove for oracle raw disks (eg. asm)?

[Matti_Kurkela]

Yes, vg00 can be moved online. (That's even one of the examples on the pvmove man page, and it mentions no special requirements.)

Of course, moving the vg's data generates quite a bit of I/O workload, so if your system is normally working near the limits of its I/O capacity, it might be best to do the vgmove operation in some quiet time, when there is not so much other workload.

"Raw disks" can mean many things.

If your raw disks are accessed by the database engine as raw LVs (/dev/vg/r), then the answer is probably yes... but if they are accessed as completely raw disks/LUNs (/dev/rdisk/disk* or /dev/rdsk/c*t*d*), then no.

MK

[Ismail Azad]

Hey seastar,

Matti's post is based on the pvmove command and it's excellent advise.

However if you are talking about the *VGMOVE* command which comes with *LVMv2* which allows you to move data from a set of disks to another, then the diskmap file does actually represent the device file of the P.V.

On the diskmap file you would specify the source and the destination which would be at the end of the day a P.V irrespective of whether it's a disk or a lun.

The_vgmove_command has absolutely no effect on high availablility which was one of the reasons of the vgmove command. Vgmove is normally associated with such migration.

However, do remember that the vgmove command CANNOT be used in_shared_mode.

Regards
Ismail Azad

[Matti_Kurkela]

Oops, I meant vgmove, but apparently wrote "pvmove" just because that command is more familiar.

MK

[seastar]

Thanks. So there is no issue with raw disks and vgmove, but may be issues with pvmove? Also what do you mean by it can't be used in shared mode?

[Ismail Azad · Accepted solution]

Hi,

Cannot be used in shared mode means in case you are in a cluster and you have associated your volume group with a vgchange -s option in the event of using Volume managers like CVM and SLVM, unless you get out of the "shared mode", you cannot perform a vgmove.

Another great thing is that if you use vgmove and for some reason the complete migration does not get carried out, your system will be in the --pre migrated-- state as it was before the firing of the command vgmove. Don't forget to assign points.

Regards
Ismail Azad

[seastar]

I am trying to do the vgmove and receive this error on vg00.

Boot disk creation must be on disk partition.

[Ismail Azad]

Hey seastar,

Probably your disk is a non-bootable disk. For an integrity server, I suppose for this migration you would require the system, O.S as well as HPSP partitions before you do the vgmove on to this disk. How about trying to create these partitions with idisk?

I say this because your error mentions a "disk partition" which could suggest the system partition is missing.

How about ioscan -funNC disk and you should see a _p1,_p2 and _p3 partitions on the disk you want to do the migration. Else create it and do the migration again with vgmove. Just a suggestion...

Regards
Ismail Azad

[Torsten.]

I have not yet used vgmove, but I assume you need to use idisk to create partitions on the destination disk, then transfer to the second partition, e.g. indicated by s2 or p2.