[Lustre-discuss] Data placement algorithm

Dilger, Andreas andreas.dilger at intel.com
Mon May 5 09:43:34 PDT 2014


Lustre does not have block replicas, relying currently on RAID at the device level.

There is an object selection policy to pick objects on OSTs. Typically it is round-robin, with some precession if multi-striped files fit evenly into the total OST count. If the free space in the OSTs is very imbalanced it shifts to weighted random placement to re-balance the OST space usage again. 

Cheers, Andreas

> On May 5, 2014, at 7:20, "Séguin Cyril" <cyril.seguin at u-picardie.fr> wrote:
> 
> Hy all,
> 
> I'm currently interesting in comparing Lustre's block replica placement policy with other placements algorithm.
> 
> Is it possible to access to the source code of Lustre's placement policy and where can I find it?
> 
> Thanks a lot.
> 
> Best regards.
> 
> CS
> 
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