[squid-users] Huge Cache / Memory Usage

Hi there,

I am working on building a cache with squid 3.1.9. I've got two
machine with 4G ram and two 500G disk each. I want to make cache as
large as possible to maximize utilization of my two big disk.

However, I soon found out I am being extremely limited by memory. lots
of swapping starts to happen when my cache exceed 9M objects. Also
everytime I want to restart cache, it would spend a hour just to
rescan all the entities into memory. and it just keep taking longer.
And From iostat -x -d , my two disk utilization is often below 5%
during scan and serving, which is kind of a waste.

from some doc, I found statement that squid needs 14M (on 64 bit) for
each 1G on disk. If that's the case, to fill 500G disk I would need
~8G ram just to hold the metadata.

So my question is:

1. Is this statement true? Can squid somehow lookup directly on the
disk to imporve disk utilization and reduce memory needs?
2. How big the cache people usually have? I think having a 500G cache
will definitely improve hit ratio and byte hit ratio, is that true?
3. what other optimization is needed for building huge cache?

Thanks in advance.
Received on Wed Dec 15 2010 - 19:17:45 MST