Stefan, On 3/10/06 12:23 PM, "Stefan Kaltenbrunner" <[EMAIL PROTECTED]> wrote:
> wrong(or rather extremely optimistic) the array itself only has two > (redundant) FC-loops(@2GB )to the attached expansion chassis. The array > has 2 active/active controllers (with a failover penalty) with two host > interfaces each, furthermore it has write-cache mirroring(to the standby > controller) enabled which means the traffic has to go over the internal > FC-loop too. > beside that the host(as I said) itself only has two HBAs @2GB which are > configured for failover which limits the hosts maximum available > bandwith to less than 200MB/S per LUN. Wow - the ickiness of SAN fro a performance / value standpoint never ceases to astound me. >> Gee - seems a long distance from 700 MB/s potential :-) > > well the array is capable of about 110MB/s write per controller head (a > bit more half the possible due to write mirroring enabled which uses > delta-syncronisation). > WAL and data are on different controllers though by default. So - you're getting 20MB/s on loading from a potential of 200MB/s? >> I would expect some 10x this if configured well. > > see above ... OTOH - configured well could include taking the disks out of the smart (?) chassis, plugging them into a dumb chassis and deploying 2 dual channel U320 SCSI adapters - total cost of about $3,000. > that might be true, though it might sound a bit harsh I really prefer to > spend the small amount of spare time I have with testing(and helping to > improve if possible) postgresql than playing with a piece of commercial > software I'm not going to use anyway ... No problem - that's our job anyway - to make the case for Postgres' use in typical large scale use-cases like the one you describe. - Luke ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org