Re: [squid-users] huge page faults

05-Apr-02 at 18:46, Henrik Nordstrom (hno@marasystems.com) wrote :
> Ok. Will put something along the following in the FAQ I think:
>
> Squid uses approximately 10 MB of ram per GB in cache_dir, plus you cache_mem
> setting and about 10-20MB extra. It is recommendable that your Squid server
> has about twice this amount of RAM or more. The extra RAM besides what is
> used by Squid is used by the operating system to improve disk I/O performance
> and by other applications or services running on the server.
>
Here's my suggestion:-

Squid uses approximately 10 MB of RAM per GB of the total of all
cache_dirs, plus your cache_mem setting and about an additional 10-20MB.
It is recommended to have at least twice this amount of physical RAM
available on your Squid server.

The extra RAM besides what is used by Squid is used by the operating
system to improve disk I/O performance and by other applications or
services running on the server. This will be true even of a server which
runs Squid as the only tcp service, since there is a minimum level of
memory needed for process management, logging, and other OS level
routines.

If you have a low memory server, and a large disk, then you will not
necessarily be able to use all the disk space, since as the cache fills
the memory available will be insufficient, forcing Squid to swap out
memory and affecting performance. A very large cache_dir total and
insufficient physical RAM + Swap could cause Squid to stop functioning
completely. The solution for larger caches is to get more physical RAM;
allocating more to Squid via cache_mem will not help.
-ends-

In the FAQ, this could be the answer to memory and performance questions,
e.g.

- how much cache_mem should I set?
- how much memory do I need for a cache_dir of xxx MB?
- I start Squid and it works well, but after a while surfing is very slow
and sometimes images don't appear.

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