Thanks Jim. I will do some test and revert back later. On 5月28日, 上午1时19分, Jim Idle <[email protected]> wrote: > Ben wrote: > > I also done some test in EMC SAN. > > If you only get the about 70MB/s for the SAN using dd. I guess your > > LV stripe size is only 4K. During my test using some disk IO > > performance tool, using 64K block size, I get the about 362MB/s > > throughput for random write IO. > > > If 362MB/s, can I say the SAN configuration is ok? > > Not really. While your stripe size can influence things like READ, > READNEXT (because it will trigger track read-ahead assuming you have > told the file system to do this), you need to remember that the jBASE > block size is 4K, not 64K and that unless your jBASE test program is > performing only sequential reads, you will never get close to the > performance of dd. In theory though a larger stripe will help some but > not all programs. If the IO is totally random it might even slow things > down as you may cause a read of a lot more data than you need. > > What happens to your tests if you use a local disk and not the SAN?> But > during the T24 COB testing, the throughput is not good as I get > > using disk IO test tool even if I have increated the stripe size to > > 64K. > > It almost certainly is not performing sequential IO, hence the closest > you will get to the iostone tests is the performance indicators given by > a large (not a few megs but a lot of gigs) random read/write mix. > Something like 6:1 read:write.> Jim, please throw some light to my issue. > > > We are using Jbase5.0.15. as database, T24 R8.003, and AIX 5.3. > > You can try to improve the performance by: > > 1) Defragmenting the jBASE files by jrf'ing them, or if they are being > resized too big (which seems to be the case lately), then writing a > script to dd them to new copies then moving them back over the original, > using a large block size with dd (to give a large chance that the > filesystem will allocate contiguous disk). > 2) Make sure the files are sized correctly of course; > 3) Take in to account the fact that there is probably transaction > journaling going on; > 4) Ask for advice from TEMENOS and the SAN supplier on tuning the SAN > for jBASE access patterns; > > First though, make your benchmarks with a local array, to give you a > base point for comparison. Then make one change at a time and re-run the > benchmarks. > > Jim
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