RE: [squid-users] squid 2 redirects but does not cache

> -----Original Message-----
> From: christophe.gravier@univ-st-etienne.fr
> [mailto:christophe.gravier@univ-st-etienne.fr]
> Sent: Monday, January 23, 2006 11:22 AM
> To: Chris Robertson
> Subject: RE: [squid-users] squid 2 redirects but does not cache
> >> -----Original Message-----
> >> From: Christophe Gravier
> >> [mailto:christophe.gravier@univ-st-etienne.fr]
> >> Sent: Sunday, January 22, 2006 5:26 AM
> >> To: squid-users@squid-cache.org
> >> Subject: [squid-users] squid 2 redirects but does not cache
> >>
> >>
>
> In fact, I wanted to run it as accelerator (with caching). In
> squid.conf I
> read:
> # NOTE: enabling httpd_accel_host disables proxy-caching and
> # ICP. If you want these features enabled also, set
> # the 'httpd_accel_with_proxy' option.
>
> So that's what I tried.
>

So it's a definition problem. It is a bit ambiguous. Generally, an accelerator accepts requests from the internet and caches pages from a small number of servers that it is "responsible" for. A proxy accepts requests from the small number of clients it is "responsible" and caches pages from the internet. Having the option enabled shouldn't hurt anything, but I think it's unnecessary.

>
> Well, I am aware of cookies (it's embedded in my plone solution).
> Regarding caching itself, I don't understand why under heavy load
> (simulated with ab apache benchmark) they are really bad
> performances and
> meanwhile I see in store.log ONLY "RELEASE" operation.

I would imagine that's fairly normal behavior for an accelerator. You should only see a CREATE action when a new object is encountered that can be cached, but isn't. SWAPOUT means that the object was in memory and was written to disk. SWAPIN is just the opposite. I think I remember reading that there is a problem with the 2.5 branch of Squid which prevents it from performing a SWAPIN (which isn't as big a problem as it sounds. Most operating systems cache file accesses to memory), but I might be mistaken. Watch the unfiltered access log. You should see some TCP_HITs and TCP_MEM_HITs. As for the poor performance, have you had a look at http://plone.org/documentation/tutorial/optimizing-plone/? The page at http://plone.org/documentation/tutorial/optimizing-plone/what-to-cache seems to have some hints at making plone play well with caches.

> In squid.conf it is
> said:
> TAG: cache_store_log
> # Logs the activities of the storage manager. Shows which
> # objects are ejected from the cache, and which objects are
> # saved and for how long. To disable, enter "none". There are
> # not really utilities to analyze this data, so you can safely
> # disable it.
>
> So it is ok to see "RELEASE" operation but I never see "store" or
> "caching" or whatever. How behave ours while accessing your pages ?
> Thanks for your tips indeed (the extension is ok and the link
> is really
> great).
> Regards,
>

I don't use the store log myself. Follow the access.log, as it shows the results of each request.

Chris
Received on Mon Jan 23 2006 - 15:10:58 MST