RW wrote:
On Wed, 23 Dec 2009 17:58:41 +0100
Matus UHLAR - fantomas <uhlar@xxxxxxxxxxx> wrote:
1. How often is the replacement done?
when the percentage of configured cache_dir size crosses the
cache_swap_high value.
I haven't looked at the code for a long-time and I only looked at 2.x,
but cache_swap_high didn't seem to play any part that I could see.
It's certainly not a simple high/low watermark algorithm.
If you run a low-volume cache the percentage never budges
from cache_swap_low (give or take a few objects), and if you shrink the
cache size a little, it corrects within a couple of minutes, whether
or not you hit the new cache_swap_high.
From http://www.squid-cache.org/Doc/config/cache_swap_high/...
The low- and high-water marks for cache object replacement.
Replacement begins when the swap (disk) usage is above the
low-water mark and attempts to maintain utilization near the
low-water mark. As swap utilization gets close to high-water
mark object eviction becomes more aggressive. If utilization is
close to the low-water mark less replacement is done each time.
Defaults are 90% and 95%. If you have a large cache, 5% could be
hundreds of MB. If this is the case you may wish to set these
numbers closer together.
Hope that helps clear it up.
Chris
