On Jan 12, 2011, at 1:25 AM, Kolesz?r ?d?m wrote: > Hi, > > I have a strange problem. I am using glusterfs 3.0.5 on 3 machines with CentOS 5.4. If I am using the mounted glusterfs intensively it is using more and more cache. I think it is normal. But as more and more cache used, it's getting slower and slower. > The glusterfsd process uses 500-700% CPU (normal 1-10%, btw it's a 8 core machine). On the mounted glusterfs a simple directory change takes about half minute, and every operation very very slow on the mounted glusterfs. > > If i execute the following command: > sync && echo 3 > /proc/sys/vm/drop_caches > > Almost the entire system memory freed, and glusterfsd CPU usage fall back 1-10%, and everything working fine.. for a while > > Now, i have to put this command into cron for every night. > > Has someone encountered the same problem? > Is there any other solution? You can set the sysctl parameter vfs_cache_pressure to a high value to make the kernel free up the cache at a higher rate. We've seen better latencies with this set to something like 10000. You can also experiment with setting vm.swappiness to 0. /etc/sysctl.conf vm.vfs_cache_pressure=10000 vm.swappiness=0 # sysctl -p ------------------------------ Vikas Gorur Engineer - Gluster, Inc. ------------------------------
