Andrei Maslennikov wrote:

On 4/13/07, *Brian J. Murrell* <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:

    On Fri, 2007-13-04 at 17:30 +0200, Andrei Maslennikov wrote:
    > Time ago we have however considered and discarded this solution
    as we
    > wanted to ensure that every file is confined to one and only one
    OSS capable
    > to deliver 0.9-1 GB/sec.

    Do you really mean OSS here or OST?  Given the 3 OSTs you would put on
    the 3 RAID cards you have in your OSS, this would meet your
    requirements
    wouldn't it?


 Hi Brian,

I meant OSS here. If our configuration would include only one OSS with 3 OSTs and the default stripe count for the file system would be 3, the solution mentioned by Andreas would be ok (and we have even considered it before asking the first question on this list). The point is, if we would be adding other 3-OST-based OSS machines to the same file system, it may so happen that the files may end up on different OSS machines (with a default stripe count of 3 one file may be split
 over 3 OSTs in three different OSS hosts).

Our main requirement is to ensure that every file ends up in one and only
 one OSS box. If this is not possible with the multi-OST OSS machines, we
may only be able to use one OST per OSS, and hence will have to stay with max 750 MB/sec single file performance per OSS.

 Best regards - Andrei.
You can use 'lfs setstripe' to designate a starting OST index, for a file or a directory. With that, you could set up different single-OSS directories. If you have more than a single client reading from an OSS at the same time, you don't even need to do that -- use three OSTs per OSS, with everything single-striped. Your multiple clients can use the different OSTs simultaneously, increasing your total performance.

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