Hi Vince. There are to limits on file descriptors on a Linux system. There is the global one, which was the one I thought you have been adjusting ( /proc/sys/kernel/fs/something) and the per process tree one, rlimits (kernel part), also known as ulimits (user space part). A Varnish server will need quite a few FDs of the first kind, not so many of the second.
So, you're right, you have a problem. Check to see whether the same problem is present at the backend. You might have a slow backend that is piling up connections. If so, you could work around the problem by setting some very agressive timeouts. You'll serve some errors, but at least the site won't go down. Per. On Mon, Jun 20, 2011 at 10:08 PM, Vince <[email protected]> wrote: > We are using CentOS 5.6 64-bit > I'll try set it to a higher number. Do we need to turn any kernel parameters > if we set it to a really high number, say 1M, on CentOS? > However, a higher number doesn't mean we have found the problem. Our varnish > server is serving about 300-400 requests per second. When it runs ok we > checked /proc/PID/fd and it uses less than 100 file descriptors. But when it > goes wrong all 65536 file descriptors have been used. Is this normal? > Thank you! > > On Tue, Jun 21, 2011 at 4:02 AM, Per Buer <[email protected]> > wrote: >> >> On Mon, Jun 20, 2011 at 9:31 PM, Vince <[email protected]> wrote >> > Hi, >> > We had a problem with our varnish server recently that sometimes the >> > server >> > will use all file descriptors available to it, which is set to 65536, >> > and >> > start refusing connections. I am wondering how to find out what's the >> > real >> > problem behind it. >> >> Why the insanely low number? Out of the box my laptop has over half a >> million. With 2minutes timeout for reuse on a tcp socket you would run >> of sockets in a jiffie - oh, wait, that's what happening. :-) >> >> I would set up waaaay up. FD's are really cheap. You could start to >> tune your TCP stack and/or reduce the number of Varnish threads but >> unless you are on a embedded system I wouldn't do it. >> >> -- >> Per Buer, CEO >> Phone: +47 21 98 92 61 / Mobile: +47 958 39 117 / Skype: per.buer >> Varnish makes websites fly! >> Whitepapers | Video | Twitter > > -- Per Buer, CEO Phone: +47 21 98 92 61 / Mobile: +47 958 39 117 / Skype: per.buer Varnish makes websites fly! Whitepapers | Video | Twitter _______________________________________________ varnish-misc mailing list [email protected] http://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
