[Gluster-users] GlusterFS 3.1.3 is available

Amar Tumballi amar at gluster.com
Fri Mar 18 17:19:10 UTC 2011


Hi Mohit,

Sorry for the delay.. answer inline..

Thanks for getting this release out. I was going through the release
> and didn't quite understand "fix layout by issuing re-balance" means.
> Does it mean if server is added or removed and then new files created
> in "existing" directory will not hash accross all the nodes (including
> new nodes)?
>
>
Currently, the hashing range/layout is different per directory, and is set
 during the mkdir(). Hence, when a new node is added, new files created
under existing directory will not be hashed to new nodes. that is handled by
issuing a 'gluster rebalance' command.

And when there is a 'remove-brick' command, the existing hash layout in the
directory will miss some ranges which belongs to those new nodes, hence
again, you would need 'gluster rebalance' which does fix the layout issues.



> And another question is it necessary to run "migrate-data" after
> running "fix-layout"? If answer is "no" then after fixing layout
> (fix-layout) wouldn't it confuse gluster hashing algorigthm in anyway
> when accessing existing files?
>
>
answer to first part of the question is 'no' (ie, you don't need to run
'migrate-data' always after 'fix-layout'). Internally the hashing algorithm
is fool proof to handle it. We have a concept called linkfile which does
this.

Regards,
Amar


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