Jim C. Nasby wrote: > Well, the problem is that you're using RAID5, which has a huge write > overhead. You're unlikely to get good performance with it. Apparently. But I had no idea that the performance hit would be that big. Running bonnie or copying a large file with dd show that the card can do 30-50 MB/sec. Running a large update on my postgresql database however, show a throughtput of ~ 2MB/sec, doing between ~ 2500 - 2300 writes/second (avarage). with an utilisation of almost always 100%, and large await times ( almost always > 700), large io-wait percentages (>50%), all measured with iostat. > Also, it sounds like sda and sdb are not mirrored. If that's the case, > you have no protection from a drive failure taking out your entire > database, because you'd lose pg_xlog. > > If you want better performance your best bets are to either > setup RAID10 or if you don't care about the data, just go to RAID0. Because it is just my development machine I think I will opt for the last option. More diskspace left. Groeten, Joost Kraaijeveld Askesis B.V. Molukkenstraat 14 6524NB Nijmegen tel: 024-3888063 / 06-51855277 fax: 024-3608416 e-mail: J.Kraaijeveld@xxxxxxxxxx web: www.askesis.nl
