Greetings, I've read a few threads like this in the archives, and had a few additional questions I was wondering if anyone could answer... Right off the bat, it seems that GlusterFS cannot make use of standard filesystem caching on the client-side. Instead, one needs to use the iocache performance translator. That works, but according to IOzone GlusterFS is just no match for NFS as far as cache performance is concerned... ~550MB/s vs. 3GB/s+ in some cases (with the GlusterFS FUSE patch). Is this known, planned-for-fix, or am I doing it wrong? :) The GlusterFS iocache in general seems to be more picky about what's cached, or perhaps I just don't know how to work it. Could someone explain the options to me? For instance... It doesn't take a genius to figure out how cache-size works (although as a side note it would be very nice if it could actually use the standard FS cache- all these questions and performance differences might disappear). For the record, I understand it is not per-thread. What about page-size? For example, if I set page-size to 1MB, and I have a 512KB file to cache, obviously it fits in 1 page. What happens to the other 512KB of space? Wasted presumably? How about if I have a 2MB file... can it consume 2 pages and be fine, or is it not cachable? Sorry, I don't have a really good grasp of paging and VM subsystems... What effect does force-revalidate-timeout have? I'm guessing that anything cached more recently than this value is automatically trusted to be correct/current, and anything over generates an mtime lookup? As you might have guessed, my main concern is client-side performance. >From my testing I'm easily able to saturate the server's gigabit link, so I'm trying to work on what can be done to let the client(s) to hit that link less often. We'll undoubtedly be using AFR and/or Unify at some point, but I don't want to have to be adding hardware just to get back up to NFS-level performance. One last quick question... what underlying filesystem do you guys like to use on GlusterFS exports? Any indication that, say, XFS scales out/up better than ext3? Many thanks in advance, Jake
