[ ... ] >> However, no matter what our configuration, dbench never shows >> any improvement. It never shows more than 25MB/sec, with 5 >> clients. I *KNOW* we are getting better throughput, but I >> need to be able to prove it.
> Dbench should not be considered a performance benchmark, but > rather only a load testing tool. The main reason dbench is > not a good benchmark tool is that it creates and deletes files > fairly rapidly, and if the file has never been written to disk > before it is deleted, it wills still count this IO in the > "bandwidth" number even though no bytes hit the disk. To add to these wise words, I reckon that "bonnie++" is also a poor benchmarking tool, regrettably very popular; I usually prefer Bonnie 1.4 for quick tests or FIO for bigger ones (both with the right options), and 'lmdd' from 'lmbench': http://www.linux-archive.org/ext3-users/284045-best-file-system-performance-analysis-tool.html Unfortunately file system benchmarking requires great patience and insight, and tool selection is part of that, including knowing why 'dbench' or 'bonnie++' are not the best performance testing tools. _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
