Manoj Govindassamy created HDFS-11412:
-----------------------------------------
Summary: Maintenance minimum replication config value allowable
range should be {0 - DefaultReplication}
Key: HDFS-11412
URL: https://issues.apache.org/jira/browse/HDFS-11412
Project: Hadoop HDFS
Issue Type: Sub-task
Components: hdfs
Affects Versions: 3.0.0-alpha1
Reporter: Manoj Govindassamy
Assignee: Manoj Govindassamy
Currently the allowed value range for Maintenance Min Replication
{{dfs.namenode.maintenance.replication.min}} is 0 to
{{dfs.namenode.replication.min}} (default=1). Users wanting not to affect the
performance of the cluster would wish to have the Maintenance Min Replication
number greater than 1, say 2. In the current design, it is possible to have
this Maintenance Min Replication configuration, but only after changing the
NameNode level Block Min Replication to 2, and which could slowdown the overall
latency for client writes.
Technically speaking we should be allowing Maintenance Min Replication to be in
range 0 to dfs.replication.max.
* There is always config value of 0 for users not wanting any
availability/performance during maintenance.
* And, performance centric workloads can still get maintenance done without
major disruptions by having a bigger Maintenance Min Replication. Setting the
upper limit as dfs.replication.max could be an overkill as it could trigger
re-replication which Maintenance State is trying to avoid. So, we could allow
the {{dfs.namenode.maintenance.replication.min}} in the range {{0 to
dfs.replication}}
{noformat}
if (minMaintenanceR < 0) {
throw new IOException("Unexpected configuration parameters: "
+ DFSConfigKeys.DFS_NAMENODE_MAINTENANCE_REPLICATION_MIN_KEY
+ " = " + minMaintenanceR + " < 0");
}
if (minMaintenanceR > minR) {
throw new IOException("Unexpected configuration parameters: "
+ DFSConfigKeys.DFS_NAMENODE_MAINTENANCE_REPLICATION_MIN_KEY
+ " = " + minMaintenanceR + " > "
+ DFSConfigKeys.DFS_NAMENODE_REPLICATION_MIN_KEY
+ " = " + minR);
{noformat}
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org
