Storage for KVM VM, FlexGroup or FlexVol?

[alessice]

Hi,

I'm set up my first AFF NetApp for hosting KVM Virtual machine, shared via NFS volume. Until now I have always used FAS with NFS for hosting many small files.

I know FlexGroup but I read that it works better with many small files.

My setup is an AFF-A250 (ontap 9.11.1) with 16 x 1,96TB SSD, that provides 2 aggregates of approximately 10TB. Volumes will be shared via NFS to 8 Linux KVM hosts.

VM disks files are relatively small, around 50GB and only someone brow up to 500GB.

Do you suggest creating two FlexVol about 10TB, one per node, or creating only one FlexGroup that can grow up to 20 TB?

Thanks

[AlexDawson · Accepted solution]

At that sort of scale, I don't think it's worth creating a flexgroup - they're beneficial for small files since the IO per volume is sequential, and that could mean operations on one constituent wouldn't necessarily block another. But in this example, since they'd be on two controllers, but mounted by one LIF, you'd have a bunch of traffic going over the cluster interconnect, which to my thinking would cancel that out.

To simplify things, you could actually consolidate all of the data partitions to one controller and just create a single aggregate and volume of ~20TB.