> Sorry for the late reply. > > The workload is a cluster of web servers with PHP serving from a single > glusterfs mount point. All web servers mount the same single share from a > file server connected via GE. > > The web servers use internal stat caches, so when serving static files the > performance is perfect. > > The problem is PHP hammering stat() for each file that gets included or > searched in include paths. PHP is always asking for the same set of about > 100 files or so. the entry/attribute timeout should definitely help in these cases. try setting it to a high value like 600 (10mins). I hoped that iocache would solve that, but I can push only 1/15 of requests, > compared to when serving directly from the backend file system. io-cache does help to a certain extent. you could also try loading write-behind and set 'option flush-behind on'. This will cut close() times even if you are not writing data. File are like 1KB each. > > Would booster help me? Is it fuse causing the latency? booster will not help you here. fuse involves context switches which are sometimes a bit too expensive for small files. You might also be interested in mod_glusterfs. This is an apache module which lets you run the filesystem inside apache address space (in a seperate thread) which can greatly boost the performance of serving static files. This module is available if you checkout glusterfs--mainline--3.0. Currently mod_glusterfs works with apache-1.3.x, but work for getting it ready for apache2.x and lighttpd is on the way. The way to use it - (in your httpd.conf) <Location /prefix> GlusterfsVolumeSpecfile "/path/to/client.vol" GlusterfsLogfile "/tmp/glusterfs.log" GlusterfsLookupCacheTimeout 600 GlusterfsStatCacheTimeout 600 GlusterfsAsyncWindowSize 65536 SetHandler "glusterfs-handler" </Location> now http://server/prefix will map to your "mountpoint". it does not yet support directory listing. use the same client.vol which you are currently using with fuse. Using io-cache with a high "option force-revalidate-timeout 600" is a good idea. Also using read-ahead for serving large static files is suggested. One important thing to notice is that while using mod_glusterfs as the client, the server authentication should be set to use 'login' instead of 'ip' (since apache would run as non root and not be able to bind to a port < 1024). see docs/auth.txt for details how to use the auth modules. mod_glusterfs is still in beta stage and any feedback would be welcome. avati
