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

[Christopher J. Morrone]

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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