Adam Litke has uploaded a new change for review.
Change subject: Live Merge: Restore watermark tracking
......................................................................
Live Merge: Restore watermark tracking
Change-Id: I632f31e7795ec5d8c6f52a480116b14470c3163f
Signed-off-by: Adam Litke <ali...@redhat.com>
---
M vdsm/virt/vm.py
1 file changed, 108 insertions(+), 10 deletions(-)
git pull ssh://gerrit.ovirt.org:29418/vdsm refs/changes/24/36924/1
diff --git a/vdsm/virt/vm.py b/vdsm/virt/vm.py
index f22610d..09080b9 100644
--- a/vdsm/virt/vm.py
+++ b/vdsm/virt/vm.py
@@ -1512,12 +1512,94 @@
with self._confLock:
self.conf['timeOffset'] = newTimeOffset
+ def _getWriteWatermarks(self):
+ def pathToVolID(drive, path):
+ for vol in drive.volumeChain:
+ if os.path.realpath(vol['path']) == os.path.realpath(path):
+ return vol['volumeID']
+ raise LookupError("Unable to find VolumeID for path '%s'", path)
+
+ volAllocMap = {}
+ statsFlags = self._libvirtBackingChainStatsFlag()
+ conn = libvirtconnection.get()
+ blkStats = conn.domainListGetStats([self._dom._dom],
+ libvirt.VIR_DOMAIN_STATS_BLOCK,
+ statsFlags)[0][1]
+ for i in xrange(0, blkStats['block.count']):
+ name = blkStats['block.%i.name' % i]
+ try:
+ drive = self._findDriveByName(name)
+ except LookupError:
+ continue
+ if not drive.blockDev or drive.format != 'cow':
+ continue
+
+ try:
+ path = blkStats['block.%i.path' % i]
+ alloc = blkStats['block.%i.allocation' % i]
+ except KeyError as e:
+ self.log.debug("Block stats are missing expected key '%s', "
+ "skipping volume", e.args[0])
+ continue
+ volID = pathToVolID(drive, path)
+ volAllocMap[volID] = alloc
+ return volAllocMap
+
+ def _getLiveMergeExtendCandidates(self):
+ # The common case is that there are no active jobs.
+ if not self.conf['_blockJobs'].values():
+ return {}
+
+ candidates = {}
+ watermarks = self._getWriteWatermarks()
+ for job in self.conf['_blockJobs'].values():
+ try:
+ drive = self._findDriveByUUIDs(job['disk'])
+ except LookupError:
+ # After an active layer merge completes the vdsm metadata will
+ # be out of sync for a brief period. If we cannot find the old
+ # disk then it's safe to skip it.
+ continue
+
+ if not drive.blockDev:
+ continue
+
+ if job['strategy'] == 'commit':
+ volumeID = job['baseVolume']
+ else:
+ self.log.debug("Unrecognized merge strategy '%s'",
+ job['strategy'])
+ continue
+ res = self.cif.irs.getVolumeInfo(drive.domainID, drive.poolID,
+ drive.imageID, volumeID)
+ if res['status']['code'] != 0:
+ self.log.error("Unable to get the info of volume %s (domain: "
+ "%s image: %s)", volumeID, drive.domainID,
+ drive.imageID)
+ continue
+ volInfo = res['info']
+
+ if volInfo['format'].lower() != 'cow':
+ continue
+
+ if volumeID in watermarks:
+ self.log.debug("Adding live merge extension candidate: "
+ "volume=%s allocation=%i", volumeID,
+ watermarks[volumeID])
+ candidates[drive.imageID] = {
+ 'alloc': watermarks[volumeID],
+ 'physical': int(volInfo['truesize']),
+ 'capacity': int(volInfo['apparentsize']),
+ 'volumeID': volumeID}
+ else:
+ self.log.warning("No watermark info available for %s",
+ volumeID)
+ return candidates
+
def _getExtendCandidates(self):
ret = []
- # FIXME: mergeCandidates should be a dictionary of candidate volumes
- # once libvirt starts reporting watermark information for all volumes.
- mergeCandidates = {}
+ mergeCandidates = self._getLiveMergeExtendCandidates()
for drive in self._devices[hwclass.DISK]:
if not drive.blockDev or drive.format != 'cow':
continue
@@ -4771,6 +4853,14 @@
jobsRet[jobID] = entry
return jobsRet
+ def _libvirtBackingChainStatsFlag(self):
+ # Since libvirt 1.2.13, the virConnectGetAllDomainStats API will return
+ # block statistics for all volumes in the chain when using a new flag.
+ try:
+ return libvirt.VIR_CONNECT_GET_ALL_DOMAINS_STATS_BACKING
+ except AttributeError:
+ return 0
+
def merge(self, driveSpec, baseVolUUID, topVolUUID, bandwidth, jobUUID):
if not caps.getLiveMergeSupport():
self.log.error("Live merge is not supported on this host")
@@ -4815,6 +4905,8 @@
if res['info']['voltype'] == 'SHARED':
self.log.error("merge: Refusing to merge into a shared volume")
return errCode['mergeErr']
+ baseSize = int(res['info']['apparentsize'])
+ baseCow = bool(res['info']['format'].lower() == 'cow')
# Indicate that we expect libvirt to maintain the relative paths of
# backing files. This is necessary to ensure that a volume chain is
@@ -4865,13 +4957,19 @@
# blockCommit will cause data to be written into the base volume.
# Perform an initial extension to ensure there is enough space to
- # copy all the required data. Normally we'd use monitoring to extend
- # the volume on-demand but internal watermark information is not being
- # reported by libvirt so we must do the full extension up front. In
- # the worst case, we'll need to extend 'base' to the same size as 'top'
- # plus a bit more to accomodate additional writes to 'top' during the
- # live merge operation.
- self.extendDriveVolume(drive, baseVolUUID, topSize)
+ # copy all the required data. If libvirt supports monitoring of
+ # backing chain volumes, just extend by one chunk now and monitor
+ # during the rest of the operation. Otherwise, extend now to
+ # accomodate the worst case scenario: no intersection between the
+ # allocated blocks in the base volume and the top volume.
+ if drive.blockDev and baseCow:
+ if self._libvirtBackingChainStatsFlag():
+ self.extendDrivesIfNeeded()
+ else:
+ extendSize = baseSize + topSize
+ self.log.debug("Preemptively extending volume %s with size %i"
+ "(job: %s)", baseVolUUID, extendSize, jobUUID)
+ self.extendDriveVolume(drive, baseVolUUID, extendCurSize)
# Trigger the collection of stats before returning so that callers
# of getVmStats after this returns will see the new job
--
To view, visit http://gerrit.ovirt.org/36924
To unsubscribe, visit http://gerrit.ovirt.org/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I632f31e7795ec5d8c6f52a480116b14470c3163f
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Adam Litke <ali...@redhat.com>
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