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https://issues.apache.org/jira/browse/HBASE-6358?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13428291#comment-13428291
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Todd Lipcon commented on HBASE-6358:
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hmm... I don't know if I thought about it in a huge amount of detail. The
original idea was to allow you to run an MR on one cluster, and then
"LoadIncrementalHFiles" on your HBase cluster which uses a different HDFS. I
was thinking there would be an advantage here over the distcp-then-load
approach, because the region server doing the copy would end up with a local
replica after the load.
That said, I didn't think through the timeout implications, which seems to be
the issue discussed in this JIRA.
As for how to determine if they're the same, the .equals() call is supposed to
do that, but perhaps it's not working right?
> Bulkloading from remote filesystem is problematic
> -------------------------------------------------
>
> Key: HBASE-6358
> URL: https://issues.apache.org/jira/browse/HBASE-6358
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.94.0
> Reporter: Dave Revell
> Assignee: Dave Revell
> Attachments: 6358-suggestion.txt, HBASE-6358-trunk-v1.diff,
> HBASE-6358-trunk-v2.diff, HBASE-6358-trunk-v3.diff
>
>
> Bulk loading hfiles that don't live on the same filesystem as HBase can cause
> problems for subtle reasons.
> In Store.bulkLoadHFile(), the regionserver will copy the source hfile to its
> own filesystem if it's not already there. Since this can take a long time for
> large hfiles, it's likely that the client will timeout and retry. When the
> client retries repeatedly, there may be several bulkload operations in flight
> for the same hfile, causing lots of unnecessary IO and tying up handler
> threads. This can seriously impact performance. In my case, the cluster
> became unusable and the regionservers had to be kill -9'ed.
> Possible solutions:
> # Require that hfiles already be on the same filesystem as HBase in order
> for bulkloading to succeed. The copy could be handled by
> LoadIncrementalHFiles before the regionserver is called.
> # Others? I'm not familiar with Hadoop IPC so there may be tricks to extend
> the timeout or something else.
> I'm willing to write a patch but I'd appreciate recommendations on how to
> proceed.
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