[Lustre-discuss] Random OST Numbers chosen in a stripe

[Kevin Van Maren]

Johann Lombardi wrote:
> On Fri, Jul 29, 2011 at 04:49:28PM -0400, Roger Spellman wrote:
>   
>> For a different file:
>>
>>    obdidx           objid          objid            group
>>      13            6884         0x1ae4                0
>>      28            6880         0x1ae0                0
>>      44            6880         0x1ae0                0
>>      27            6880         0x1ae0                0
>>
>> Why is this?
>>
>> How can I control it to always be sequential?
>>     
>
> It depends on the OST usage imbalance and you can tune the stripe allocation policy with qos_threshold_rr. For more information, please refer to the lustre manual:
> http://wiki.lustre.org/manual/LustreManual20_HTML/LustreProc.html#50438271_pgfId-1296529
>
> Cheers,
> Johann
>   

Also note that newer versions of Lustre sort the OST list even in RR 
mode, so that it will not allocate successive objects from the same OSS 
node.

Kevin