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https://issues.apache.org/jira/browse/HADOOP-2577?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Bryan Duxbury updated HADOOP-2577:
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Fix Version/s: 0.17.0
> [hbase] Scaling: Too many open file handles to datanodes
> --------------------------------------------------------
>
> Key: HADOOP-2577
> URL: https://issues.apache.org/jira/browse/HADOOP-2577
> Project: Hadoop Core
> Issue Type: Bug
> Components: contrib/hbase
> Reporter: stack
> Fix For: 0.17.0
>
>
> We've been here before (HADOOP-2341).
> Today the rapleaf gave me an lsof listing from a regionserver. Had thousands
> of open sockets to datanodes all in ESTABLISHED and CLOSE_WAIT state. On
> average they seem to have about ten file descriptors/sockets open per region
> (They have 3 column families IIRC. Per family, can have between 1-5 or so
> mapfiles open per family -- 3 is max... but compacting we open a new one,
> etc.).
> They have thousands of regions. 400 regions -- ~100G, which is not that
> much -- takes about 4k open file handles.
> If they want a regionserver to server a decent disk worths -- 300-400G --
> then thats maybe 1600 regions... 16k file handles. If more than just 3
> column families..... then we are in danger of blowing out limits if they are
> 32k.
> We've been here before with HADOOP-2341.
> A dfsclient that used non-blocking i/o would help applications like hbase
> (The datanode doesn't have this problem as bad -- CLOSE_WAIT on regionserver
> side, the bulk of the open fds in the rapleaf log, don't have a corresponding
> open resource on datanode end).
> Could also just open mapfiles as needed, but that'd kill our random read
> performance and its bad enough already.
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