On 3/26/09 11:01 AM, "Dingwell, Robert A. (BOBD)" <bobd@xxxxxxxxx> wrote: > I¹ve been trying to get a caching architecture setup so that if a server I > am caching content for goes down or is more likely just unavailable to do > network issues I can have the cache serve up the stale content. In the > production environment that this will be used I will not have the ability to > have all of the services involved set cache control headers on their data. We > are operating on a wan with people all over the globe so it would be really > difficult to get everyone to do that. What I can do though is to make sure > that everything goes through apache acting as a reverse proxy which then sets > the Cache-Control header, which I have done and verified that it does indeed > do what I want it to. > > So now I fire up squid and apache and attempt to access a server I have > control over and I get back the data I expect to get back. Look in the squid > log file see the header in the log ³Cache-Control: stale-if-error=300² so I > know it¹s being sent. Now I shutdown the server I just accessed and attempt > to access the same url. I expect to get back the same data that I just got > back but instead I get back the error page saying the service is unavailable. > Shouldn¹t squid be serving up the stale content? Or am I missing a step. The > other odd thing is once I start the server back up it takes a couple of > minutes to get back the page from server as squid seams to be caching the > error page. > > I know that stale-if-error is only going to work for 500-504 errors but > looking through the squid logs again I see that I am getting an error code > back when I try to access the page when it¹s down ³HTTP/1.1 503 Service > Temporarily Unavailable². > > One last thing this article , http://www.mnot.net/blog/2007/12/12/stale , > makes it sound like squid has a configuration parameter that is used to enable > stale-if-error even when the server does not send the control header. Does > anyone know if this exists or what the magic incantation is to get it working? > > Anybody have any ideas as to what I may be doing wrong, or an alternative > approach to accomplishing what I am trying to get working? I already tried > using offline mode which did not work and I think isn¹t really what I would > want to do anyway as I need squid to attempt to access the server and serve up > the stale data only when the server is down. > > Any help is appreciated , > > Thanks > Rob
