On Tue, Feb 21, 2012 at 05:17:20PM +0100, Jiri Denemark wrote: > Migrating qemu domains with disks using cache != none is unsafe unless > the disk images are stored on coherent clustered filesystem. Thus we > forbid migrating such domains unless VIR_MIGRATE_UNSAFE flags is used. > > This series uses similar aproach to forbidding unsafe PCI passthrough > or disk format probing when we forbade those by default with the > possibility to force them. > > Domain configuration is only checked on source, which makes migrating > affected domains from an old libvirt to the new one possible. Migrating > back is impossible since destination libvirtd would complain about > unknown flag (the flag is not filtered so it gets to the destination > even though it's not really used there). > > However, users of clustered filesystems now have to always pass the new > flag to be able to migrate because libvirtd would think they are doing > something unsafe. Perhaps we should provide a system wide (i.e., > /etc/libvirt/qemu.conf) tunable which would disable cache mode checking > for all domains at once? I think we should add a virStorageFileIsClusterFS(const char *path) and whitelist the filesystem magic that we know is ok. I expect GFS, GFS2, OCFS2 would be a good starting point. We already do this for virStorageFileIsSharedFS() in migration, so this is no worse Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list