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Stephen Yuan Jiang updated HBASE-18036: --------------------------------------- Summary: HBase 1.x : Data locality is not maintained after cluster restart or SSH (was: Data locality is not maintained after cluster restart or SSH) > HBase 1.x : Data locality is not maintained after cluster restart or SSH > ------------------------------------------------------------------------ > > Key: HBASE-18036 > URL: https://issues.apache.org/jira/browse/HBASE-18036 > Project: HBase > Issue Type: Bug > Components: Region Assignment > Affects Versions: 1.4.0, 1.3.1, 1.2.5, 1.1.10 > Reporter: Stephen Yuan Jiang > Assignee: Stephen Yuan Jiang > Fix For: 1.4.0, 1.3.2, 1.1.11, 1.2.7 > > Attachments: HBASE-18036.v0-branch-1.1.patch, > HBASE-18036.v0-branch-1.patch, HBASE-18036.v1-branch-1.1.patch, > HBASE-18036.v2-branch-1.1.patch > > > After HBASE-2896 / HBASE-4402, we think data locality is maintained after > cluster restart. However, we have seem some complains about data locality > loss when cluster restart (eg. HBASE-17963). > Examining the AssignmentManager#processDeadServersAndRegionsInTransition() > code, for cluster start, I expected to hit the following code path: > {code} > if (!failover) { > // Fresh cluster startup. > LOG.info("Clean cluster startup. Assigning user regions"); > assignAllUserRegions(allRegions); > } > {code} > where assignAllUserRegions would use retainAssignment() call in LoadBalancer; > however, from master log, we usually hit the failover code path: > {code} > // If we found user regions out on cluster, its a failover. > if (failover) { > LOG.info("Found regions out on cluster or in RIT; presuming failover"); > // Process list of dead servers and regions in RIT. > // See HBASE-4580 for more information. > processDeadServersAndRecoverLostRegions(deadServers); > } > {code} > where processDeadServersAndRecoverLostRegions() would put dead servers in SSH > and SSH uses roundRobinAssignment() in LoadBalancer. That is why we would > see loss locality more often than retaining locality during cluster restart. > Note: the code I was looking at is close to branch-1 and branch-1.1. -- This message was sent by Atlassian JIRA (v6.4.14#64029)