determining number of CPUS

[skasu]

hi
i am responsible for building a oltp application, i have to start from determining the system architecture, the unix flavor
and everything.

i would like to know if there is a way to determine the number of CPUs that will be sufficient (or minimum), provided that I already know the number of concurrent users and number of
transactions.

Thanks of help

skasu

[Chandra]

Give us more detail please.
ie. # of transactions, database size etc.

Thanks.

[skasu]

chandra,

the database size is going to be approximately 20G
the number of transactions 200
the number of users 200

[Halo]

I think 2 CPUs would be enough.

[skasu]

hi halo,

thanks for the answer.

could you please let me know the reasoning behind this solution. my manager wants to know.

Thank you

skasu

[Halo]

Your db is OLTP, so there will be multiple small transactions, which will not utilize a lot of CPU. My db has 250 transactions, 200 sessions (though only about 100 are in use at any moment in time), is a hybrid db, it's mainly OLTP but there is a batch process that runs for about 10 min once a day ... all this on 1 CPU. Judging from this I think you will not need more than 2 CPUs, though I think 1 might be enough.

[marist89]

Hmmm. No disrespect intended, but 200 users on 2 cpus sounds a little small to me.

It really depends on how much work will be done on the server. True, in an OLTP environment the transactions should be small. However, if there is alot of back-end computation involved, 2 CPUs will not be enough.

Your best bet would be to get a server that has the ability to scale to 4 or 6 processors. You could start with 2 processors and see if your application becomes CPU bound. You can justify to management that you want to add 1 cpu easier than you can justify a new server.