After a bit more testing, this only happens when I am using GlusterFS as my VM store. In the above report, /mnt/vmstore is a GlusterFS mount (running Gluster 3.3beta). If I edit my nova.conf to remove "--instances_path", so that the default instance directofy of /var/lib/nova/instances is used instead, cache="None" seems to be accepted fine.
That begs the question of whether specifying "cache=none" across the board is really ideal.
I'm not sure what the correct setting should be for user with GlusterFS. Perhaps documenting this potential tripping point is sufficient.
After a bit more testing, this only happens when I am using GlusterFS as my VM store. In the above report, /mnt/vmstore is a GlusterFS mount (running Gluster 3.3beta). If I edit my nova.conf to remove "--instances_path", so that the default instance directofy of /var/lib/ nova/instances is used instead, cache="None" seems to be accepted fine.
That begs the question of whether specifying "cache=none" across the board is really ideal.
I'm not sure what the correct setting should be for user with GlusterFS. Perhaps documenting this potential tripping point is sufficient.