Re: [squid-users] throughput limitation from cache

At 1137142598s since epoch (01/12/06 21:56:38 -0500 UTC), Richard Mittendorfer wrote:
> Well, can't reach this here. Cached ~260KkB/s. And I'm quite sure the
> file was still in the linux disk cache. What does your cache_dir looks
> like? aufs I assume.

27GB on our root filesystem:

cache_dir aufs /var/spool/squid 27000 16 256

> Since you've got plenty of RAM - maybe this is the reason?

Could be; I've thrown 1GB of RAM to cache_mem, so I should be holding
a fair amount of stuff. Additionally, I've tuned the swap to a large
cache size. Finally, the maximum_object_size is 160MB to make sure
I'm keeping large OS updates on hand (saves us a lot of time for OS
patches).

I've set the "swapiness" of the linux kernel to a low level, to
prevent it from swapping too aggressively.

> Or it's some kind of autotuned by download speeds? Can't think of.

What are you using for your speed tests? I'm using wget, so I know
there's no browser cache issue.

Also, what network are you testing on? If I use our 802.11 wireless
network, I can't get much over 280-300KB/s, because I start to bump up
against the 11Mb/s limit of WIFI. The 2MB/s rate I quoted you earlier
was over switch 100Mb/s ethernet.

> The IDE HD's that carries the storage are spun down most of the
> time.

You don't think you're waiting on spinup for some of these requests,
do you? What's the largest file you've downloaded? If it's small
enough, any spinup time might adversely affect your average bitrate.

HTH,

Jason

-- 
Jason Healy
http://www.logn.net/