[jira] [Updated] (HBASE-2821) Keep young storefiles at lower replication

["Andrew Purtell (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HBASE-2821?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrew Purtell updated HBASE-2821:
----------------------------------

    Fix Version/s: 2.0.0

> Keep young storefiles at lower replication
> ------------------------------------------
>
>                 Key: HBASE-2821
>                 URL: https://issues.apache.org/jira/browse/HBASE-2821
>             Project: HBase
>          Issue Type: Improvement
>          Components: regionserver
>            Reporter: Todd Lipcon
>             Fix For: 2.0.0
>
>         Attachments: HBASE-2821.patch, lifetime-distribution.png, storefile_age.pl
>
>
> jgray and I were brainstorming some ideas about this:
> In a typical heavy-write scenario, many store files do not last very long. They're flushed and then within a small number of seconds a compaction runs and they get deleted. For these "short lifetime" store files, it's less likely that a failure will occur during the window in which they're valid. So, I think we can consider some optimizations like the following:
> - Flush files at replication count 2. Scan once a minute for any store files in the region that are older than 2 minutes. If they're found, increase their replication to 3. (alternatively, queue them to avoid scanning)
> - More dangerous: flush files at replication count 1, but don't count them when figuring log expiration. So, if they get lost, we force log splitting to recover.
> The performance gain here is that we avoid the network and disk transfer of writing the third replica for a file that we're just about to delete anyway.



--
This message was sent by Atlassian JIRA
(v6.2#6252)