Commit 41e1e79e authored by Apollon Oikonomopoulos's avatar Apollon Oikonomopoulos Committed by Iustin Pop
Browse files

Pause DRBD sync for OS install if not wait_for_sync

When wait_for_sync is set to False in LUInstanceCreate, Ganeti lets DRBD sync
in the background while performing the rest of the installation steps,
including OS installation.

However, OS installation is a very disk-intensive task that intereferes badly
with the background I/O caused by DRBD's initial sync. To this end, we pause
the background sync before OS installation and unpause it afterwards, which
yields a significant speed boost for OS installation. The following should be

a) The user has requested not to wait for sync, i.e. the instance will be
   non-redundant for an unspecified interval anyway and delaying this by a
   couple of minutes is not a big compromise.

b) This approach is also followed during disk wiping.
Signed-off-by: default avatarApollon Oikonomopoulos <>
[ simplify an if check]
Signed-off-by: default avatarIustin Pop <>
Reviewed-by: default avatarIustin Pop <>
parent a6a3efe4
......@@ -8861,10 +8861,30 @@ class LUInstanceCreate(LogicalUnit):
if iobj.disk_template != constants.DT_DISKLESS and not self.adopt_disks:
if self.op.mode == constants.INSTANCE_CREATE:
if not self.op.no_install:
pause_sync = (iobj.disk_template in constants.DTS_INT_MIRROR and
not self.op.wait_for_sync)
if pause_sync:
feedback_fn("* pausing disk sync to install instance OS")
result = self.rpc.call_blockdev_pause_resume_sync(pnode_name,
iobj.disks, True)
for idx, success in enumerate(result.payload):
if not success:
logging.warn("pause-sync of instance %s for disk %d failed",
instance, idx)
feedback_fn("* running the instance OS create scripts...")
# FIXME: pass debug option from opcode to backend
result = self.rpc.call_instance_os_add(pnode_name, iobj, False,
if pause_sync:
feedback_fn("* resuming disk sync")
result = self.rpc.call_blockdev_pause_resume_sync(pnode_name,
iobj.disks, False)
for idx, success in enumerate(result.payload):
if not success:
logging.warn("resume-sync of instance %s for disk %d failed",
instance, idx)
result.Raise("Could not add os for instance %s"
" on node %s" % (instance, pnode_name))
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