We got a server w/ 8GB of RAM for caching lots of small objects in
reverse proxy mode.
I calculated that 32bit squid uses about 115 bytes per object, 64bit
squid uses 165 bytes.
Here's how I calculated it:
squid mem usage = cat /proc/<squid pid>/stat|awk '{print $23}'
objects in cache = snmpwalk -v 2c -c public server:3401
.1.3.6.1.4.1.3495.1.3.1.7
cost per object = (mem use) / (obj in cache)
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w/ 64 squid, I would allocate 7.5GB of RAM to squid, 512 MB to
OS. (7.5GB / 165 bytes) = 48,806,446 objects
w/ 32bit squid, I'll run 2 instances of squid, each squid have access
to 3.5GB of memory. 1GB of memory will be allocated for OS, overhead, etc
2 * (3.5GB /115 bytes) = 65,358,198 objects.
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conclusion: w/ large amount of memory, it's better to run multiple
instances of squid if you want to maximize the number of objects you
can store. In my configuration, I can store 25% more
objects. Obviously, this setup would be a little more complex to maintain.
If anyone know of a better way to maximize the amount of objects
squid can store or have any comments, please let me know.
mike
