lvm/openstack: stripe all volumes and distribute them round robin on PVs

[Bernd <ecki@zusammenkunft.net>]

Hello,

when using local lvm2 logical volumes for OpenStack Nova ephemeral pool then the created logical volumes are linear (not striped) and what is worse than that, all volumes are allocated on the same first physical volume (until it is filled up).

I made a ServerFault question about that:

https://serverfault.com/questions/849088/automatically-distribute-lvm-stripes-for-specific-lvm2-vg-on-linux/849255#849255

It was suggested that raid_stripe_all_devices should help (to turn on striping by default), but it did not. So I went ahead and patched the lvm.py of nova to turn the striping on. However I still wonder if there is a lvm option (allocation policy for that).

Besides that, it looks like it is still creating the first stripe on the first device. It would make more sense to have it (even in the linear case) to round robin the LVs. Because first of all it might be the most busy part of the volume and secondly it helps for keeping room for expanding volumes.

Is there anything planned in this direction?

Gruss

Bernd

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