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..:-)



Egotism, n:     Doing the New York Times crossword puzzle with a pen.Egotist, n:       
person of low taste, more interested in himself than me.                -- Ambrose 
"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])

Reply via email to