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https://issues.apache.org/jira/browse/HBASE-12770?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrew Purtell updated HBASE-12770:
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Comment: was deleted
(was: Thanks for your concern. I agree that it will be helpful to balance
replication loads among region servers if we know queue depths of peers. The
coordinator could be the master, or on the other hand, I am not sure whether we
can have a method to conduct stable balanced replication loads for peers
without the central coordinator. As an optional way, the RS could know the
total queued hlog count if every RS report their queue depths, then each RS
could compute the average replication load based on the current alive RS count
when transferring queues, this might help the RS to better decide whether to
transfer a queue. I will work on the detail to have a try.)
> Don't transfer all the queued hlogs of a dead server to the same alive server
> -----------------------------------------------------------------------------
>
> Key: HBASE-12770
> URL: https://issues.apache.org/jira/browse/HBASE-12770
> Project: HBase
> Issue Type: Improvement
> Components: Replication
> Reporter: cuijianwei
> Priority: Minor
>
> When a region server is down(or the cluster restart), all the hlog queues
> will be transferred by the same alive region server. In a shared cluster, we
> might create several peers replicating data to different peer clusters. There
> might be lots of hlogs queued for these peers caused by several reasons, such
> as some peers might be disabled, or errors from peer cluster might prevent
> the replication, or the replication sources may fail to read some hlog
> because of hdfs problem. Then, if the server is down or restarted, another
> alive server will take all the replication jobs of the dead server, this
> might bring a big pressure to resources(network/disk read) of the alive
> server and also is not fast enough to replicate the queued hlogs. And if the
> alive server is down, all the replication jobs including that takes from
> other dead servers will once again be totally transferred to another alive
> server, this might cause a server have a large number of queued hlogs(in our
> shared cluster, we find one server might have thousands of queued hlogs for
> replication). As an optional way, is it reasonable that the alive server only
> transfer one peer's hlogs from the dead server one time? Then, other alive
> region servers might have the opportunity to transfer the hlogs of rest
> peers. This may also help the queued hlogs be processed more fast. Any
> discussion is welcome.
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