On Apr 13, 2007 12:00 +0200, Andrei Maslennikov wrote: > We are currently evaluating possible commodity hardware candidates > suitable for a single OSS with a single OST served to the clients via the > IB/RDMA. The goal is to provide the peak performance around 1 GB/sec > for large streaming I/O for a single file at the client level, *without* > striping. > In other words, we want to see if we could build a high performance > standalone box which would be acting as a Lustre Head for a couple > of clients (obviously, we will have to run also the metadata service on it). > > Now comes the interesting point: if we run a single write process against > a striped logical volume built upon the three available drives, we only are > able to obtain 750 MB/sec. The writer process eats 100% of CPU, and > there is no way to improve this. This behaviour, of course, is perfectly > normal, but for us this means that if we would base our OST on this > combination of CPU + striped volume, we probably will never be able to > spit out more than 750 MB/sec peak i/o perf to the clients. Unless > the OST backend service itself is multithreaded!
You should try with 3 OSTs on the box, and set the filesystem default stripe count to 3 and see if the mutli-threading on the client can work better than that in LVM. You will get 3x as many requests in flight, 3x as much write cache space in Lustre. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. _______________________________________________ Lustre-discuss mailing list [EMAIL PROTECTED] https://mail.clusterfs.com/mailman/listinfo/lustre-discuss
