PHP App user limit per server

[redhatlab]

Hi,

I am wondering how can I know when it is time to add more servers to a balanced setup of web servers, database slave servers and master database?

The number seems to be from 10K to 15K users per web server, how can I know I am not over using the servers or not using them at full capacity?

Each web server has 16 processor with 32 GB of ram, each DB has same amount of processor, plus RAID 10 for the DB and 16GB of ram. All servers are interconnected on a private network with two nic cards; one nic for the public network and the other for the private.

I am just missing to implement memcached for the SQL objects and the HTML pages (an existing cache system is on place working like a charm for the HTML pages). Will this last "thing" push the limit from 10K/15K to 20K/30K per server?

Thank you.

[eelixduppy]

Not sure and the best way is to test it. Caching techniques can greatly reduce the server load, though, so you should definitely try it and see what happens. Sorry I don't have any specific answer for you, but you will notice a difference.

And Welcome to WebmasterWorld!