VG Size Allocation Suggestion

[Steven Chen_1]

Hello,

We have a VA7100 with 4x36G drive space (comes up with 45G available, anyway).

I would like to have comments from guru about what size to allocate VG. Someone suggest that one vg is better to consist of multiple drives that are not bigger than 10G. In VA technology, you can create lun as a drive, so you can create more drives as wish. My question is would there be any difference if we make one vg consisting of one 20G drive or two 10G drives? With VA, would disk size be a matter?

Any help is very appreciated, as always.

Steven

[Leif Halvarsson_2]

Hi
I am not quite sure I understand your question correct.
As I understand the VA7100 array works somewhat different from ordinary "RAID boxes" as it always stripes the data across evry physical disk. In this case it should make no difference (performance or security) how you create your lun's. With "ordinary" raid technology, the more drives you use in a RAID-set the better performance you get.

[Amruth]

Hi,

Both are equal from the LVM point of view.
According to performance it is better 2*10GB.

Regards,
AR

[David Bell_1]

Steven,

It is best to create at least (2)LUNS or as you described, "disks" per Volume Group. The reason for this is performnce from the interfaces. This is of course assuming you have (2) fibre channel interfaces going to (2) controllers on the VA7100 or to a fibre channel switch. This allows you to alternate the primary controller for each LUN. This provides the ability for an alternate link as well as both Host Bus Adapters being utilized.

HTH,

Dave