On Thursday 24 June 2010 15:16:05 Janning wrote: > On Thursday 24 June 2010 14:53:57 Matthew Wakeling wrote: > > On Thu, 24 Jun 2010, Janning wrote: > > > We have a 12 GB RAM machine with intel i7-975 and using > > > 3 disks "Seagate Barracuda 7200.11, ST31500341AS (1.5 TB)" > > > > > For each drive, you will be able to read/write approximately 8kB / > > 0.0085s, giving 941kB per second. If you have multiple processes all > > doing random access, then you may be able to utilise both discs and get > > double that. > > So with your calculation I have a maximum of 2MB/s random access. So i > really need to upgrade my disk configuration! i was looking at tomshardware.com and the fastest disk is Maxtor Atlas 15K II * 8K147S0,SAS,147 GB, 16 MB Cache,15000 rpm with 5.5 ms random access time. So even if i switch to those disks i can only reach a perfomace gain of 1.5, right? To achieve a better disk performance by factor of ten, i need a raid-10 setup with 12 disks (so i have 6 raid-1 bundles). Or are there other factors with high end disks? kind regards Janning -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
