LVM and Nike disk array

[Breukelman R.E.]

We have a Nike disk array with 5 x 2.1 Gb disks and 5 x 4.2 Gb disks, both in RAID5, resulting in a disk of 8 Gb en one disk of 16 Gb.
Each disk is in a separate volumegroup with one logical volume each. The specifications of the disks in diskinfo output is the same, except for the 'size' and 'blocks per disk' values.

I want to extend the logical volume (with the 16 Gb disk) with the 8 Gb disk (which contains no data anymore). The way i want to do this is removing the volumegroup of the 8 Gb disk and add the disk to the volumegroup of the 16 Gb disk. Then extend the logical volume and the filesystem using both the 8 and 16 Gb disks.

My question is: is there any possible problem with adding a disk with a different capacity to an already existing filesystem?

Rene Breukelman

[James R. Ferguson]

Hi:

You certainly can add or build volume groups with different size physical volumes.

However, the values of 'max_pe', 'max_pv, 'max_le' and 'pe_size' are fixed during the initial volume group creation. In the absence of an explicit specification, the 'max_pe' is established based on the largest physical disk. This often means that while larger physical volumes can be added later, they will not be able to be totally used. The only work around in that case is to recreate the volume group from scratch.

Regards!

...JRF...

[Sanjay_6]

Hi,

We are required to do that all the time. you cannot have the same size of disks everytime. so a mix of big and small disks is okay.

Hope this helps.

Regds

[fg_1]

Hi there

It's no problem mixing drives, I have a similar setup for my depot server where I have 6 18GB disk and 10 9GB disk lumped together.

James is 100% correct in his posting about the max_pe size being based on the extent size of the larger drives. This shouldn't be an issue for you at all.

Good luck.

[Helen French]

hey,

U can easily do that ! Remove the LV and VGs from the 8GB HDD first, then extend the other VG with this 8GB. Then u may extend the LV and the filesystem.

It will be so easy, if u do throgh SAM

HTH,
Shiju

[Anthony deRito]

This should work fine for you. Those NIKEs are an older type disk array but they still got some nice features. Have you created alternate links using dual SPs? You need to have option package 2 on your SPs. You also need to bind a set of disks to the alternate SP by binding through the alternate SP interface. Good luck.

Tony