On 06/12/2012 08:22 AM, Sabyasachi Ruj wrote: > I am having a problem with glusterfs and kernel file buffer cache. > I've been able to reduce the problem to a simple case to demonstrate > the behavior: > ... I tried running this with RHS 2.0+ (what you would know as GlusterFS 3.3+, from current git HEAD) under RHEL 6.2 on my machines. What I saw was that FUSE *doesn't even send us the read* in most cases, not even reliably when we poke /proc/sys/vm/drop_caches (which seems to me like it should *always* result in a read). It shows up in strace because that's before FUSE, but we're after FUSE. If I set a breakpoint on fuse_readv_resume, for example, I don't reach it until we do an open for another process - at which point the original process does see the new data. This can be avoided by using attribute-timeout=0 and entry-timeout=0, which are unfortunately available in the "glusterfs" command but not in mount.glusterfs AFAICT. With these options we still don't see the change immediately, but we do get called when drop_caches is invoked.
