[jira] [Commented] (ACCUMULO-3303) funky performance with large WAL

["Josh Elser (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ACCUMULO-3303?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14237399#comment-14237399 ] 

Josh Elser commented on ACCUMULO-3303:
--------------------------------------

FYI [~afuchs], I just closed out ACCUMULO-3308 which added some more documentation to the user manual on the recommendations for tserver.wal.blocksize. Not sure if you thought of something else that you might want to do here code-wise.

> funky performance with large WAL
> --------------------------------
>
>                 Key: ACCUMULO-3303
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3303
>             Project: Accumulo
>          Issue Type: Bug
>          Components: logger, tserver
>    Affects Versions: 1.6.1
>            Reporter: Adam Fuchs
>         Attachments: 1GB_WAL.png, 2GB_WAL.png, 4GB_WAL.png, 512MB_WAL.png, 8GB_WAL.png, WAL_disabled.png
>
>
> The tserver seems to get into a funky state when writing to a large write-ahead log. I ran some continuous ingest tests varying tserver.walog.max.size in {512M, 1G, 2G, 4G, 8G} and got some results that I have yet to understand. I was expecting to see the effects of walog metadata management as described in ACCUMULO-2889, but I also found an additional behavior of ingest slowing down for long periods when using a large walog size.
> The cluster configuration was as follows:
> {code}
> Accumulo version: 1.6.2-SNAPSHOT (current head of origin/1.6)
> Nodes: 4
> Masters: 1
> Slaves: 3
> Cores per node: 24
> Drives per node: 8x1TB data + 2 raided system
> Memory per node: 64GB
> tserver.memory.maps.max=2G
> table.file.compress.type=snappy (for ci table only)
> tserver.mutation.queue.max=16M
> tserver.wal.sync.method=hflush
> Native maps enabled
> {code}



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