On Thu, 12 May 2005, Joost de Heer wrote:
I have a Squid process running on RedHat 3 ES (Taroon). The machine has 2 GB memory. At the moment, the Squid process is 418 MB large, but 200 MB of this is in swap. Is this normal?
Yes.
This is your OS writing out mostly idle pages to swap before there is a shortage of memory.
What you need to watch out for is swapins. (see vmstat 5 output or your favorite OS performance monitor). If you see swapins then Squid will suffer badly (if these is for Squid).
I have irregularly dips on the proxy, when the request rate and throughput halves (from 200 req/s to slightly over 100, and from 1.2MB throughput to 0.7), and at the moment, the only thing that seems strange is the usage of swap.
You could try to run without swap enabled.
The swap space is really used by Squid: When I stop the proxy, swap space is cleared.
This is also quite normal, considering you do not have any other big processes running. It is however not Squid's choice to use swap, it is your OS which decides overall performance is probably better if swap is used (which in this case is an false assumption).
Regards Henrik
