hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "stack (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-6233) [brainstorm] snapshots: hardlink alternatives
Date Sat, 07 Jul 2012 20:59:34 GMT

    [ https://issues.apache.org/jira/browse/HBASE-6233?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13408771#comment-13408771
] 

stack commented on HBASE-6233:
------------------------------

bq. The time is (fs.rename() * nfiles + fs.symlink() * nfiles), but is just a metadata operation
on HDFS.

Can take a while I've found.  Something to be aware of.

bq. And by doing this you need to add some logic to the current code to don't read the .del
files

Yes.  It'd be ugly especially compared to symlinking w/ refcounting.

bq. So we just need to come up with an alternative to hardlink....

Smile.  Yes.
                
> [brainstorm] snapshots: hardlink alternatives
> ---------------------------------------------
>
>                 Key: HBASE-6233
>                 URL: https://issues.apache.org/jira/browse/HBASE-6233
>             Project: HBase
>          Issue Type: Brainstorming
>            Reporter: Matteo Bertozzi
>            Assignee: Matteo Bertozzi
>         Attachments: Restore-Snapshot-Hardlink-alternatives.pdf
>
>
> Discussion ticket around snapshots and hardlink alternatives.
> (See the HDFS-3370 discussion about hardlink and implementation problems)
> (taking for a moment WAL out of the discussion and focusing on hfiles)
> With hardlinks available taking snapshot will be fairly easy:
> * (hfiles are immutable)
> * hardlink to .snapshot/name to take snapshot
> * hardlink from .snapshot/name to restore the snapshot
> * No code change needed (on fs.delete() only one reference is deleted)
> but we don't have hardlinks, what are the alternatives?

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message