[Lustre-discuss] how the lustre distribute data among disks within one OST

[Jaln]

Oh, I mean there is one file, for example 6 MB, the stripe size is 1MB, and
only 2 OST,
then the file will be divided into 6 stripes, denoted as stripe 0,1,2,3,4,5.
the distribution on the 2 OST  would be stripe 0,2,4 on OST0, stripe 1,3,5
on OST1.

Jaln


On Thu, Jun 13, 2013 at 2:54 PM, Christopher J. Morrone
<morrone2 at llnl.gov>wrote:

> I think you may be confused about what a stripe is in Lustre.  If there
> are only 2 OST, then you can only stripe a file across 2.
>
> Or maybe I don't understand your terminology.  I don't know what you mean
> by "0,4" and "0,2".
>
>
> On 06/13/2013 02:38 PM, Jaln wrote:
>
>> if I have 6 stripes, 2 OST, using round-robin striping,
>> stripe 0,2,4 will be on OST0,
>> stripe 1,3,5 will be on OST1,
>> Do you guys have any idea about what will be the difference of accessing
>> stripe 0,4 vs stripe 0,2?
>> stripe 0, 2 seems to be closer than 0,4, or the lustre will do
>> some intelligent work?
>>
>> Jaln
>>
>>
>> On Thu, Jun 13, 2013 at 10:22 AM, Christopher J. Morrone
>> <morrone2 at llnl.gov <mailto:morrone2 at llnl.gov>> wrote:
>>
>>     On 06/13/2013 05:19 AM, E.S. Rosenberg wrote:
>>      > On Thu, Jun 13, 2013 at 3:09 AM, Christopher J. Morrone
>>      > <morrone2 at llnl.gov <mailto:morrone2 at llnl.gov>> wrote:
>>      >> Lustre does not  manage the individual disks.  I sits on top of a
>>      >> filesystem, either ldiskfs(basically ext4) or zfs (as of Lustre
>>     2.4).
>>      > Is ZFS the recommended fs, or just an option?
>>      > Doesn't ZFS suffer major performance drawbacks on linux due to it
>>      > living in userspace?
>>      > Thanks,
>>      > Eli
>>
>>     LLNL (Brian Behlendorf) ported ZFS natively to Linux.  We are not
>> using
>>     the FUSE (userspace) version.  You can find it at:
>>
>>     http://zfsonlinux.org
>>
>>     ZFS is one of the two backend filesystem options for Lustre, as of
>>     Lustre 2.4.  2.4 is the first Lustre release that fully supports using
>>     ZFS.  Here at LLNL we are using it on our newest, and largest at 55PB,
>>     filesystem.
>>
>>     Chris
>>
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>>
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>>
>>
>>
>>
>> --
>>
>> Genius only means hard-working all one's life
>>
>>
>


-- 

Genius only means hard-working all one's life
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