On 02/06/11 18:27, Tory M Blue wrote:
Afternoon
Have a question, is there a negative to running -k rotate more than
once a day?
All your active connections will pause while Squid deals with the logs.
I've recently moved squid to a ramcache (it's glorious), however my
cache.swap file continues to grow and brings me to an uncomfortable
95%.
By "ramcache" do you mean RAM cache (aka a large cache_mem storage area)
or an in-memory pseudo disk?
Tried using COSS? (in-memory pseudo disk with hardware backing).
If I run rotate it goes from 95% to 83% (9-12gb cache dir), it seems I
need to run this once every 12 hours to stay in a good place, but is
there anything wrong with that? I don't see it and seems that the
rotate really just cleans up the swap file and since it's all in ram,
it's super fast.
That should be fine even if its was on disk. High throughput networks
are known to do it as often as every 3 hours with only minor problems.
I've only heard of one network doing it hourly, the pause there was
undesirable for the traffic being handled.
There is a nasty little feedback loop: the faster to *have* to do it
the worse is the effects when you do. It is economical, up to a point.
Another option is to move the swap file to a physical disk, what type
of performance hit will my squid system take? Obviously it's just
looking up, reading hash so it should not cause any issues, but
wondered. What is my best option, keep everything in ram and run
rotate 2-3x a day or is the penalty so small that pushing the swap
file to a physical disk a better answer?
Unsure. Try it and let us know.
The swap.state is a journal with small async writes for each file
operation (add/remove/update of the cache_dir), including those for
temporary files moving through. You only get into problems if the write
speed to it falls behind the I/O of the cache its recording. (in
general, on average etc.. Peak bursts should not be a big problem)
Squid can recover from most swap.state problems. But it is best to
avoid that kind of thing becoming normal.
HTH
Amos
--
Please be using
Current Stable Squid 2.7.STABLE9 or 3.1.12
Beta testers wanted for 3.2.0.8 and 3.1.12.2
