[lustre-discuss] What happens if my stripe count is set to more than my number of stripes

Drokin, Oleg oleg.drokin at intel.com
Mon Apr 20 10:01:54 PDT 2015


Oh, I see.
Well, nothing will be written at the other OSTs since this file does not have data, but objects would be allocated still and sit empty. If you decide to write more data to that file - the data will go into the additional OSTs. If no data will ever go there the objects would just sit zero-sized.

On Apr 20, 2015, at 12:53 PM, <Prakrati.Agrawal at shell.com>
 wrote:

> Hi,
> 
> I have 165 OSTs. Right now the problem is that because of the file size and stripe size set as 64 GB and 1GB respectively and 64 ranks, the stripes to be written by each rank come out to be 1GB each.
> Now if I set my stripe count to 128, rank1 will write stripe 1 on OST 1, rank 2 will write stripe 2 on OST 2 and so on. After 64 stripes, all data is written, then what will be written on the rest of the remaining 64 OSTs.
> 
> 
> -----Original Message-----
> From: Drokin, Oleg [mailto:oleg.drokin at intel.com] 
> Sent: Monday, April 20, 2015 10:14 PM
> To: Agrawal, Prakrati PTIN-PTT/ICOE
> Cc: <lustre-discuss at lists.lustre.org>
> Subject: Re: [lustre-discuss] What happens if my stripe count is set to more than my number of stripes
> 
> Hello!
> 
>   Current allocator behaviour is such that when you specify more stripes than you have OSTs, it'll treat it the same as if you set stripe count to -1 (that is - the maximum possible stripes).
> 
> Bye,
>    Oleg
> On Apr 20, 2015, at 4:47 AM, <Prakrati.Agrawal at shell.com>  <Prakrati.Agrawal at shell.com> wrote:
> 
>> Hi,
>> 
>> I have a doubt regarding Lustre file system. If I have a file of size 64 GB and I set stripe size to 1GB, my number of stripes become 64. But if I set my stripe count as 128, what does the Lustre do in that case?
>> 
>> Thanks and Regards,
>> Prakrati
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>> lustre-discuss mailing list
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>> http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
> 
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