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Ted Yu commented on HBASE-24: ----------------------------- Should we take further action on this JIRA ? > Scaling: Too many open file handles to datanodes > ------------------------------------------------ > > Key: HBASE-24 > URL: https://issues.apache.org/jira/browse/HBASE-24 > Project: HBase > Issue Type: Bug > Components: regionserver > Reporter: stack > Priority: Blocker > Fix For: 0.92.0 > > Attachments: HBASE-823.patch, MonitoredReader.java > > > 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. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira