AIX 5.2 convert to BIG VG

[rondebbs]

Hello,

We currently have a standard VG with 30 PVs. I need to add an additional 30 but the limit for a standard VG is 32 PVs. Is there a way I can convert this VG to a "big" VG so that I take advantage of the 128 PV limit. I'm hoping I can do the conversion without taking any kind of outage.

 

[ogniemi]

man chvg


-B Changes the volume group to Big VG format. This can accommodate up to 128 physical volumes and 512 logical volumes.
Notes:

1. The -B flag cannot be used if there are any stale physical partitions.
2. Once the volume group is converted, it cannot be imported into AIX 4.3.1 or lower versions.
3. The -B flag cannot be used if the volume group is varied on in concurrent mode.
4. There must be enough free partitions available on each physical volume for the VGDA expansion for this operation to be successful.
5. Because the VGDA resides on the edge of the disk and it requires contiguous space for expansion, the free partitions are required on the edge of the disk. If those partitions are allocated for user usage, they will be migrated to other free partitions on the same disk. The rest of the physical partitions will be renumbered to reflect the loss of the partitions for VGDA usage. This will change the mappings of the logical to physical partitions in all the PVs of this VG. If you have saved the mappings of the LVs for a potential recovery operation, you should generate the maps again after the completion of the conversion operation. Also, if the backup of the VG is taken with the map option and you plan to restore using those maps, the restore operation may fail since the partition number may no longer exist (due to reduction). It is recommended that backup is taken before the conversion, and right after the conversion if the map option is utilized.
6. Because the VGDA space has been increased substantially, every VGDA update operation (creating a logical volume, changing a logical volume, adding a physical volume, and so on) may take considerably longer to run.

 

[rondebbs]

Thanks ogn, good info. It sounds like I can do the
chvg -B with the VG varied on and the file systems mounted and in use.