How to create a PVG

 
Kavita Poonia
Regular Advisor

How to create a PVG

I have got 4 PVs in the volume group and I want to make a PVG comprising of those four disks.These four disks have data written on them.

Kindly suggest how should I go ahead.

Thanks a lot......
2 REPLIES 2
Sajjad Sahir
Honored Contributor

Re: How to create a PVG

PVG comprising what is the meaning of it
Matti_Kurkela
Honored Contributor

Re: How to create a PVG

PVG= Physical Volume Group.

It is not at all the same as VG.

It is a tool for determining how the LVM allocates extents from disks.

For example, if you have 2 SCSI buses with 2 disks each and you're planning to mirror your disks, you might want to make sure that two halves of the same mirror will never end up on the same SCSI bus. Otherwise, a failure of a single bus could bring down the entire mirror set.

The solution is to assign the disks to PVGs, with one PVG for each SCSI bus. Then you can switch the LVM volume group allocation policy to "PVG-strict" (lvchange -s g ). That means, when mirroring an extent, the mirror must be on different PVG than the original... so it is forced to go on a disk that is on a different bus.

Kavita, based on your later thread, I guess you already found out how to create PVGs?

MK
MK