[jira] [Commented] (SOLR-13029) Allow HDFS buffer size to be configured

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[jira] [Commented] (SOLR-13029) Allow HDFS buffer size to be configured

JIRA jira@apache.org

    [ https://issues.apache.org/jira/browse/SOLR-13029?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16711366#comment-16711366 ]

Tim Owen commented on SOLR-13029:

Updated to be specific to the copying of index files to/from HDFS during backups and restores. Would be configured in solr.xml using e.g.
    <repository name="hdfs" class="org.apache.solr.core.backup.repository.HdfsBackupRepository" default="false">
      <int name="solr.hdfs.buffer.size">262144</int>
There is another method in {{HdfsBackupRepository}}, {{openInput}} that is only used for opening small metadata files or getting the checksum during restores, so I have left that using the default buffer size. Only the bulk whole-file copying uses the larger buffer.

> Allow HDFS buffer size to be configured
> ---------------------------------------
>                 Key: SOLR-13029
>                 URL: https://issues.apache.org/jira/browse/SOLR-13029
>             Project: Solr
>          Issue Type: Improvement
>      Security Level: Public(Default Security Level. Issues are Public)
>          Components: Backup/Restore, hdfs
>    Affects Versions: 7.5, master (8.0)
>            Reporter: Tim Owen
>            Priority: Major
>         Attachments: SOLR-13029.patch, SOLR-13029.patch
> There's a default hardcoded buffer size setting of 4096 in the HDFS code which means in particular that restoring a backup from HDFS takes a long time. Copying multi-GB files from HDFS using a buffer as small as 4096 bytes is very inefficient. We changed this in our local build used in production to 256kB and saw a 10x speed improvement when restoring a backup. Attached patch simply makes this size configurable using a command line setting, much like several other buffer size values.

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