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Posted to common-dev@hadoop.apache.org by "Bryan Duxbury (JIRA)" <ji...@apache.org> on 2008/01/31 00:39:34 UTC
[jira] Updated: (HADOOP-2577) [hbase] Scaling: Too many open file
handles to datanodes
[ https://issues.apache.org/jira/browse/HADOOP-2577?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Bryan Duxbury updated HADOOP-2577:
----------------------------------
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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