When trying to zero out an LVM snapshot on precise the kernel sometimes
hangs when performing the dd. Also the dd process itself can take
an extremely long time even when it does succesfully complete.
This can be up to 30 minutes for a 1 Gig volume/snapshot.
I believe this is a kernel specific issue with LVM snapshots. The
zeroing process is unreliable and can cause kernel hangs to let's remove it.
In order to protect against data leakage we'll implement the zeroing process
on volume creation. This doesn't seem to have a significant impact and doesn't
suffer from the same isues tha zeroing out an LVM snapshot does.
No reason to continue zero on delete, the zero on creation should
probably be sufficient.
Doesn't seem to cause any timing issues but need to keep this in mind.
Reviewed: https:/ /review. openstack. org/12457 github. com/openstack/ cinder/ commit/ 1b3322d45fe2c5e d72cc7f8674e5e3 19928065ad
Committed: http://
Submitter: Jenkins
Branch: master
commit 1b3322d45fe2c5e d72cc7f8674e5e3 19928065ad
Author: John Griffith <email address hidden>
Date: Wed Sep 5 19:27:48 2012 +0000
Don't zero out snapshot volume on snapshot_delete
When trying to zero out an LVM snapshot on precise the kernel sometimes
hangs when performing the dd. Also the dd process itself can take
an extremely long time even when it does succesfully complete.
This can be up to 30 minutes for a 1 Gig volume/snapshot.
I believe this is a kernel specific issue with LVM snapshots. The
zeroing process is unreliable and can cause kernel hangs to let's remove it.
In order to protect against data leakage we'll implement the zeroing process
on volume creation. This doesn't seem to have a significant impact and doesn't
suffer from the same isues tha zeroing out an LVM snapshot does.
No reason to continue zero on delete, the zero on creation should
probably be sufficient.
Doesn't seem to cause any timing issues but need to keep this in mind.
Fixes bug 1023755
Change-Id: I56209d8e5973cf fa997b4ec3e51c3 361838386de