On Thu, 2009-07-02 at 13:34 -0600, Martin Pokorny wrote: > > While my brief testing with IOR showed acceptable write throughput to > the Lustre filesystem,
Was the IOR test file-per-client or single-file, segment-per-client? If the latter, how big was the segment and was the file being written to striped? If yes, what were it's striping parameters? > I have been unable to achieve anywhere near that > figure with our application doing the writes --- I'm concerned that the > write pattern being used is a severely limiting factor. If you need more bandwidth to the file than a single client/network connection/OSS/disk can provide, then you need to do some parallellization, as you have surmised. But the parallellization has to be effective. The most effective parallization you can get is by mapping a single client to a single OST on an unshared OSS across an unshared network connection. Frequently one or more of those components will be underutilized though so some economy can be introduced in sharing an OSS or even OST, or network connection, etc. among several clients to the limit of the performance of the shared resource. > In this > situation, does anyone have any advice about what I ought to be looking > at to improve performance on Lustre? Well, you need to figure out why your application is not able to take advantage of the parallellization as IOR has demonstrated can be achieved. Perhaps you need to (more effectively) stripe your file across some OSTs so that clients are not competing for the same OST in their write operations. b.
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