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From: jburwell <git@git.apache.org>
To: dev@cloudstack.apache.org
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References: <git-pr-1403-cloudstack@git.apache.org>
In-Reply-To: <git-pr-1403-cloudstack@git.apache.org>
Subject: [GitHub] cloudstack pull request: Taking fast and efficient volume
 snapshot...
Content-Type: text/plain
Message-Id: <20160408195703.6C5E3DFC74@git1-us-west.apache.org>
Date: Fri,  8 Apr 2016 19:57:03 +0000 (UTC)

Github user jburwell commented on a diff in the pull request:

    https://github.com/apache/cloudstack/pull/1403#discussion_r59080710
  
    --- Diff: engine/storage/datamotion/src/org/apache/cloudstack/storage/motion/StorageSystemDataMotionStrategy.java ---
    @@ -361,59 +608,225 @@ private String getProperty(long snapshotId, String property) {
         }
     
         private Map<String, String> getVolumeDetails(VolumeInfo volumeInfo) {
    -        Map<String, String> sourceDetails = new HashMap<String, String>();
    +        Map<String, String> volumeDetails = new HashMap<String, String>();
     
             VolumeVO volumeVO = _volumeDao.findById(volumeInfo.getId());
     
             long storagePoolId = volumeVO.getPoolId();
             StoragePoolVO storagePoolVO = _storagePoolDao.findById(storagePoolId);
     
    -        sourceDetails.put(DiskTO.STORAGE_HOST, storagePoolVO.getHostAddress());
    -        sourceDetails.put(DiskTO.STORAGE_PORT, String.valueOf(storagePoolVO.getPort()));
    -        sourceDetails.put(DiskTO.IQN, volumeVO.get_iScsiName());
    +        volumeDetails.put(DiskTO.STORAGE_HOST, storagePoolVO.getHostAddress());
    +        volumeDetails.put(DiskTO.STORAGE_PORT, String.valueOf(storagePoolVO.getPort()));
    +        volumeDetails.put(DiskTO.IQN, volumeVO.get_iScsiName());
     
             ChapInfo chapInfo = _volumeService.getChapInfo(volumeInfo, volumeInfo.getDataStore());
     
             if (chapInfo != null) {
    -            sourceDetails.put(DiskTO.CHAP_INITIATOR_USERNAME, chapInfo.getInitiatorUsername());
    -            sourceDetails.put(DiskTO.CHAP_INITIATOR_SECRET, chapInfo.getInitiatorSecret());
    -            sourceDetails.put(DiskTO.CHAP_TARGET_USERNAME, chapInfo.getTargetUsername());
    -            sourceDetails.put(DiskTO.CHAP_TARGET_SECRET, chapInfo.getTargetSecret());
    +            volumeDetails.put(DiskTO.CHAP_INITIATOR_USERNAME, chapInfo.getInitiatorUsername());
    +            volumeDetails.put(DiskTO.CHAP_INITIATOR_SECRET, chapInfo.getInitiatorSecret());
    +            volumeDetails.put(DiskTO.CHAP_TARGET_USERNAME, chapInfo.getTargetUsername());
    +            volumeDetails.put(DiskTO.CHAP_TARGET_SECRET, chapInfo.getTargetSecret());
    +        }
    +
    +        return volumeDetails;
    +    }
    +
    +    private Map<String, String> getSnapshotDetails(SnapshotInfo snapshotInfo) {
    +        Map<String, String> snapshotDetails = new HashMap<String, String>();
    +
    +        long storagePoolId = snapshotInfo.getDataStore().getId();
    +        StoragePoolVO storagePoolVO = _storagePoolDao.findById(storagePoolId);
    +
    +        snapshotDetails.put(DiskTO.STORAGE_HOST, storagePoolVO.getHostAddress());
    +        snapshotDetails.put(DiskTO.STORAGE_PORT, String.valueOf(storagePoolVO.getPort()));
    +
    +        long snapshotId = snapshotInfo.getId();
    +
    +        snapshotDetails.put(DiskTO.IQN, getProperty(snapshotId, DiskTO.IQN));
    +
    +        snapshotDetails.put(DiskTO.CHAP_INITIATOR_USERNAME, getProperty(snapshotId, DiskTO.CHAP_INITIATOR_USERNAME));
    +        snapshotDetails.put(DiskTO.CHAP_INITIATOR_SECRET, getProperty(snapshotId, DiskTO.CHAP_INITIATOR_SECRET));
    +        snapshotDetails.put(DiskTO.CHAP_TARGET_USERNAME, getProperty(snapshotId, DiskTO.CHAP_TARGET_USERNAME));
    +        snapshotDetails.put(DiskTO.CHAP_TARGET_SECRET, getProperty(snapshotId, DiskTO.CHAP_TARGET_SECRET));
    +
    +        return snapshotDetails;
    +    }
    +
    +    private HostVO getHost(SnapshotInfo snapshotInfo) {
    +        HostVO hostVO = getHost(snapshotInfo.getDataCenterId(), true);
    +
    +        if (hostVO == null) {
    +            hostVO = getHost(snapshotInfo.getDataCenterId(), false);
    +
    +            if (hostVO == null) {
    +                throw new CloudRuntimeException("Unable to locate an applicable host");
    +            }
             }
     
    -        return sourceDetails;
    +        return hostVO;
         }
     
    -    public HostVO getHost(long dataStoreId) {
    -        StoragePoolVO storagePoolVO = _storagePoolDao.findById(dataStoreId);
    +    private HostVO getHost(Long zoneId, boolean computeClusterMustSupportResign) {
    +        if (zoneId == null) {
    +            throw new CloudRuntimeException("Zone ID cannot be null.");
    +        }
     
    -        List<? extends Cluster> clusters = _mgr.searchForClusters(storagePoolVO.getDataCenterId(), new Long(0), Long.MAX_VALUE, HypervisorType.XenServer.toString());
    +        List<? extends Cluster> clusters = _mgr.searchForClusters(zoneId, new Long(0), Long.MAX_VALUE, HypervisorType.XenServer.toString());
     
             if (clusters == null) {
    -            throw new CloudRuntimeException("Unable to locate an applicable cluster");
    +            clusters = new ArrayList<>();
             }
     
    +        Collections.shuffle(clusters, new Random(System.nanoTime()));
    +
    +        clusters:
             for (Cluster cluster : clusters) {
                 if (cluster.getAllocationState() == AllocationState.Enabled) {
                     List<HostVO> hosts = _hostDao.findByClusterId(cluster.getId());
     
                     if (hosts != null) {
    +                    Collections.shuffle(hosts, new Random(System.nanoTime()));
    +
                         for (HostVO host : hosts) {
                             if (host.getResourceState() == ResourceState.Enabled) {
    -                            return host;
    +                            if (computeClusterMustSupportResign) {
    +                                if (computeClusterSupportsResign(cluster.getId())) {
    +                                    return host;
    +                                }
    +                                else {
    +                                    // no other host in the cluster in question should be able to satisfy our requirements here, so move on to the next cluster
    +                                    continue clusters;
    +                                }
    +                            }
    +                            else {
    +                                return host;
    +                            }
                             }
                         }
                     }
                 }
             }
    --- End diff --
    
    *I realize that this thought is beyond the scope of this PR, and completely understand if the answer is no.*
    
    Would it be possible to replace the outer ``for`` loop and ``if`` block with a new method on the HostDAO to get all allocated, enabled hosts for a list of clusters?  It would not only reduce the load on the database and make the performance profile of this method more deterministic, but it would make it much easier to read.


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