On Thu, Jan 21, 2016 at 02:10:02PM -0500, John Ferlan wrote:
On 12/23/2015 10:06 AM, Wido den Hollander wrote:
This allows user to use the volume wiping functionality of the libvirt storage driver.
This patch also adds a new wiping algorithm VIR_STORAGE_VOL_WIPE_ALG_DISCARD
By default the VIR_STORAGE_VOL_WIPE_ALG_ZERO algorithm is used and with RBD this will called rbd_write() in chunks of the underlying object size to completely zero out the volume.
With VIR_STORAGE_VOL_WIPE_ALG_DISCARD it will call rbd_discard() in the same object size chunks which will trim/discard all underlying RADOS objects in the Ceph cluster.
Signed-off-by: Wido den Hollander <wido@widodh.nl> --- include/libvirt/libvirt-storage.h | 4 + src/storage/storage_backend_rbd.c | 155 +++++++++++++++++++++++++++++++++++++- tools/virsh-volume.c | 2 +- 3 files changed, 159 insertions(+), 2 deletions(-)
Found these buried in my todo list of things to look at from during the holiday break. I figure by bumping it'll bring it back into focus... "Semantically" speaking - this patch is a v2 of the original patch series...
I'm still a bit conflicted whether to add a new option to Wipe or whether a new API should be developed. I see value in both options. Although perhaps thinking of this as "trim" and not "discard" could make it more palatable for wipe. As a new API, each backend driver could decide whether it supports the discard/trim option, but that's quite a bit more work (essentially mimic the Wipe functionality, but generate Trim).
I think I can certainly see a dedicated API for trim in the future, as there's use cases for trim beyond full-disk wiping. eg to spars-ify a disk image. I think its still ok to add trim to the existing Wipe API though, as a specific targetted use case. Regards, 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 :|