On Tue, 11 May 2004, Bjoern Metzdorf wrote: > Hi, > > I am curious if there are any real life production quad processor setups > running postgresql out there. Since postgresql lacks a proper > replication/cluster solution, we have to buy a bigger machine. > > Right now we are running on a dual 2.4 Xeon, 3 GB Ram and U160 SCSI > hardware-raid 10. > > Has anyone experiences with quad Xeon or quad Opteron setups? I am > looking at the appropriate boards from Tyan, which would be the only > option for us to buy such a beast. The 30k+ setups from Dell etc. don't > fit our budget. > > I am thinking of the following: > > Quad processor (xeon or opteron) > 5 x SCSI 15K RPM for Raid 10 + spare drive > 2 x IDE for system > ICP-Vortex battery backed U320 Hardware Raid > 4-8 GB Ram
Well, from what I've read elsewhere on the internet, it would seem the Opterons scale better to 4 CPUs than the basic Xeons do. Of course, the exception to this is SGI's altix, which uses their own chipset and runs the itanium with very good memory bandwidth. But, do you really need more CPU horsepower? Are you I/O or CPU or memory or memory bandwidth bound? If you're sitting at 99% idle, and iostat says your drives are only running at some small percentage of what you know they could, you might be memory or memory bandwidth limited. Adding two more CPUs will not help with that situation. If your I/O is saturated, then the answer may well be a better RAID array, with many more drives plugged into it. Do you have any spare drives you can toss on the machine to see if that helps? Sometimes going from 4 drives in a RAID 1+0 to 6 or 8 or more can give a big boost in performance. In short, don't expect 4 CPUs to solve the problem if the problem isn't really the CPUs being maxed out. Also, what type of load are you running? Mostly read, mostly written, few connections handling lots of data, lots of connections each handling a little data, lots of transactions, etc... If you are doing lots of writing, make SURE you have a controller that supports battery backed cache and is configured to write-back, not write-through. ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
