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Date: Fri, 29 Aug 2014 15:26:53 +0000 (UTC)
From: "Keith Turner (JIRA)" <jira@apache.org>
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Message-ID: <JIRA.12737597.1409267876940.2637.1409326013298@arcas>
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Subject: [jira] [Commented] (ACCUMULO-3090) VolumeChooser should be able to
 decide per-file
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    [ https://issues.apache.org/jira/browse/ACCUMULO-3090?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14115325#comment-14115325 ] 

Keith Turner commented on ACCUMULO-3090:
----------------------------------------

One backup option starting w/ 1.5 is exporting tables.  Can clone, offline, export.. leaving original table online while distcp copies exported files.  Would need to write a little script to do all tables in an instance.

> VolumeChooser should be able to decide per-file
> -----------------------------------------------
>
>                 Key: ACCUMULO-3090
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3090
>             Project: Accumulo
>          Issue Type: Improvement
>    Affects Versions: 1.6.0
>            Reporter: Christopher Tubbs
>
> Currently, the VolumeChooser decides only once per-tablet which volume to use for that tablet. The directory is "sticky" after the decision is made. This can cause unexpected behavior for users, which makes it harder to manage volume usage/capacity.
> One unexpected behavior is that data will still be written to an existing tablet's predetermined volume, even if the volume is removed from instance.volumes.
> Another unexpected behavior this causes for users is when adding a new volume. One might expect to compact tablets after adding a new volume, and have the new usage to be balanced across all the volumes (using the provided RandomVolumeChooser), but due to the stickiness, that is not the behavior seen. Instead, only new tablets (from new tables, or new splits) will begin to randomly use the new volume.
> If the sticky behavior is desired, a volume chooser could still do that, by accepting a "preferredTabletVolume"/"preferredTabletDirectory" in its environment, provided by the caller, to use to make decisions.


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