Hi, On Tue, Jul 01, 2008 at 11:16:15AM -0700, Skye Poier Nott wrote: > I want to deploy Varnish with very large cache sizes (200GB or more) > for large, long lived file sets. Is it more efficient to use large > swap or large mmap in this scenario? > > According to the FreeBSD lists, even 20GB of swap requires 200MB of > kern.maxswzone just to keep track of it, so it doesn't seem like that > will scale too well. Is one or the other method better for many small > files vs less many big files?
My experience with Varnish on FreeBSD with long lived (~1 week) large data sets tells me that using the file storage backend easily gives you 60-70 second hangs. The malloc backend works smoother. I've been using 256 MB maxswzone on a few servers with upto 80 GB of data in the swap and did not have any problems with maxswzone beeing too small. That said, I do get large peaks in number of threads and vm faults with peak/high traffic, which makes it difficult to scale further. I don't know if this is due to bottlenecks in the VM subsystem, Varnish or if I have too little RAM. But I hope to find out more about it. I suspect there is more work needed in this area to be done by the developers. PS: FreeBSD supports swap devices upto only 32 GB, so you may need to split your disks/volumes up in many partitions. Bye, -- Anders. _______________________________________________ varnish-misc mailing list [email protected] http://projects.linpro.no/mailman/listinfo/varnish-misc
