On Wed, May 02, 2018 at 09:36:10AM +0200, Christian Ehrhardt wrote: > Hi, > by discussing on bug [1] we found an issue in the ZFS storage backend. > When one defines a zfs pool through XML (virsh pool-create --build) a top > level ZFS pool will be created and works fine. The virsh pool-define-as > counterpart to this is: > > $ fallocate -l 100M /tmp/Mzfs > $ sudo zpool create Mzfs /tmp/Mzfs > $ virsh pool-define-as --name zfs --source-name Mzfs --type zfs > $ virsh pool-start zfs > $ virsh vol-create-as --pool zfs --name vol1 --capacity 10M > $ virsh vol-list --pool zfs > vol1 /dev/zvol/Mzfs/vol1 > $ virsh pool-refresh zfs > Pool zfs refreshed > $ virsh vol-list --pool zfs > vol1 /dev/zvol/Mzfs/vol1 > > Ok, all fine so far. > But if one wants to use a zfs-FS as sub-pool things work a while but fail > as soon as pool info is refreshed. > > $ fallocate -l 100M /tmp/Xzfs > $ sudo zpool create Xzfs /tmp/Xzfs > $ sudo zfs create Xzfs/images > $ virsh pool-define-as --name Xzfs --source-name Xzfs/images --type zfs > I ended with the pool not being started (expected after pool-define-as), > but then > $ virsh pool-start Xzfs > $ virsh vol-create-as --pool Xzfs --name vol1 --capacity 10M > $ virsh vol-list --pool Xzfs > vol1 /dev/zvol/Xzfs/images/vol1 > $ virsh pool-refresh zfs > Pool zfs refreshed > $ virsh vol-list --pool Xzfs > # no output anymore > > We happened to find this in the libvirt log: > error : virCommandWait:2601 : internal error: Child process (/sbin/zpool > get -Hp health,size,free,allocated Xzfs/images) unexpected exit status 1: > cannot open 'Xzfs/images': invalid character '/' in pool name > > So it seems the data refresh would need to become aware of filesytems and > strip this to the basename before doing the call. > This comes from src/storage/storage_backend_zfs.c > > cmd = virCommandNewArgList(ZPOOL, > "get", "-Hp", > "health,size,free,allocated", > def->source.name, > NULL); > # fails > zfs list -Hp -t volume -r -o name,volsize,refreservation Xzfs/images > # would work > zfs list -Hp -t volume -r -o name,volsize,refreservation Xzfs > > But there might be more to it than what I see, either more changes needed > to fully work with subpools or intentionally not working with them. > For the latter we should still consider improving the error handling, like > refusing right away with a reasonable message on "virsh pool-define-as". > > I wondered if one with more experience in that area of libvirt would be > willing to pick this up or has an opinion why it would not need to be > changed that I might be missing? I don't really know anything about the ZFS pool in libvirt, but it superficially looks like a genuine libvirt bug we should try to fix. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
