Hi, we have a write performance problem that I hope maybe someone could shed some light on.
we have two linux servers, roughly equivalent regarding CPUs and memory running the same OS version (Kernal 2.4 SuSe 8.1) and the same version of sapdb with almost identical configuration (as far as I can tell relevant for write performance). We noticed a big difference in write performance (we have a little java tool that issues many inserts and commits each 100 records), i.e. one system is 5 times faster than the others, while read performance is nearly identical. The main diffference is that the fast system uses a RAID5 system while the slow system uses a fast scsi disc. since this is an obvious thing to look for we performed filesystem benchmarks using the IOzone benchmark tool (http://www.iozone.org) and found a big difference in the write (in IOzone terms, writing to a newly created file) performance for small block sizes, that would explain the difference in database write performance as the order of magnitude of the difference is roughly that of the difference in insert-performance. However, the rewrite performance (in IOzone terms, writing to an already existing file) is even better for the "slow" system. I thought sapdb writes to existing files and therefore that number is the relevant one destroying my theory that disc write performance is the problem. Another strange thing is that on the "slow" machine stopping the database also takes ages compared to the "fast" system. Can anyone explain that or take a guess? Thanks, Robert _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
