From 41e1e79ec919ff9f92b945d11af1fe597b75e57a Mon Sep 17 00:00:00 2001
From: Apollon Oikonomopoulos <apollon@noc.grnet.gr>
Date: Wed, 3 Aug 2011 18:03:38 +0300
Subject: [PATCH] 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
noted:
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: Apollon Oikonomopoulos <apollon@noc.grnet.gr>
[iustin@google.com: simplify an if check]
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>
---
lib/cmdlib.py | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 038bbb6a2..a70dda0cd 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -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,
self.op.debug_level)
+ 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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