On 24 Jul 2003 at 15:54, Kasim Oztoprak wrote: > The questions for this explanation are: > 1 - Can we use postgresql within clustered environment? > 2 - if the answer is yes, in which method can we use postgresql within a > cluster? > active - passive or active - active?
Coupled with linux-HA( See http://linux-ha.org) heartbeat service, it *should* be possible to run postgresql in active-passive clustering. If postgresql supported read-only database so that several nodes could read off a single disk but only one could update that, a sort of active-active should be possible as well. But postgresql can not have a read only database. That would be a handy addition in such cases.. > Now, the second question is related to the performance of the database. Assuming we > have a > dell's poweredge 6650 with 4 x 2.8 Ghz Xeon processors having 2 MB of cache for > each, with the > main memory of lets say 32 GB. We can either use a small SAN from EMC or we can put > all disks > into the machines with the required raid confiuration. > > We will install RedHat Advanced Server 2.1 to the machine as the operating system > and postgresql as > the database server. We have a database having 25 millions records having the > length of 250 bytes > on average for each record. And there are 1000 operators accessing the database > concurrently. The main > operation on the database (about 95%) is select rather than insert, so do you have > any idea about > the performance of the system? Assumig 325 bytes per tuple(250 bytes field+24-28 byte header+varchar fields) gives 25 tuples per 8K page, there would be 8GB of data. This configuration could fly with 12-16GB of RAM. After all data is read that is. You can cut down on other requirements as well. May be a 2x opteron with 16GB RAMmight be a better fit but check out how much CPU cache it has. A grep -rwn across data directory would fill the disk cache pretty well..:-) HTH Bye Shridhar -- Egotism, n: Doing the New York Times crossword puzzle with a pen.Egotist, n: A person of low taste, more interested in himself than me. -- Ambrose Bierce, "The Devil's Dictionary" ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
