On Mon, 2004-11-29 at 11:32, Martin Marji Cermak wrote:
Hello guys,
I have been playing with Squid under a heavy load and there are some stats.
I am trying to maximise the "Byte Hit Ratio" value. I got 13% average, but I am not happy about this number - I want it higher (how to do it?). There are thousands of ADSL clients using the cache and I want to know what the Squid limits are.
USED HARDWARE: Processor: P4 1.8GHz Memory: 1 GB Hardisk: 40 GB IDE 7200rpm Controler: Serverworks Chipset Ethernet card: Broadcom TG3
ACHIEVED PERFORMANCE: Byte Hit Ratio: 13% (TOO LOW !!!)
You want to save bandwidth or you want speed??
Yes, I want to Save bandwidth.
USED CONFIGURATION: maximum_object_size 51200 KB (SHOULD I MAKE IT HIGHER ???)
I made mine to cache up to 40MB only. If you really want to have more byte hit ratio, then by all means, up the max_obj_size.
OK, now I have: maximum_object_size 200 MB
cache_dir aufs /cache 25000 16 256 (one ide disk, see the spec above)
This seems too low. I used 40GB of the 80GB drive
OK, I changed it to cache_dir aufs /cache 92000 16 256
cache_mem 8 MB200 MB. More being cached to memory. Faster retrieval.
Thank you, nice. I just hope it does not start swaping :-)
I am in a testing phase, trying to find out what can just one squid handle - what are its limits. Then I will install a little Squid farm.The Squid is configured as a transparet proxy, so: httpd_accel_uses_host_header on httpd_accel_with_proxy OFF (yes, transparent) httpd_accel_port 80 httpd_accel_host virtual
Say.. do you have any experience running a load balanced squid? I'm wondering, since it's transparent, what happens if Squid Goes down? (for X Reasons?) What happens to your ADSL users? (in the thousands??)
If Squid goes down, it drops all established connections. So, I am supposed to have my Squid in a good shape :-), stable and running without stopping/crashing.
The "thousands" means approx. 3500 users at the moment.
Yes, you are righ, I was logging quite a lot. I modified the debug module a bit (I can set a debug level for each module, e.g.:Are you logging a lot of things? If you are, your IDE disk may not be able to sustain the throughput.
debug_options ALL,1;14,2;99,4
) so now I log only info I need
And another interesting thing:
My median Byte Hit Ratio has reached 17% (200 MB max file, 95 GB cache).
So I drecompiled squid with --enable-removal-policies and set:
cache_replacement_policy heap LFUDA
It looks I can gain a couple of percent (LFUDA should have a bit better Byte Hit Ratio than lfu).
I will report some stats to the list, when I have more info (after I run squid in this configuration for more days).
Have a nice day, Marji
