On Fri, 2005-02-18 at 00:45 +0800, David Teigland wrote: > On Thu, Feb 17, 2005 at 10:47:55AM -0500, Manuel Bujan wrote: > > Hello, > > > > Is there anyway to improve the performance of a cman based gfs cluster > > installation tunning some of its parameters ? > > > > We are using the dlm style locking mechanism in a two node 100 GB shared > > gfs cluster with a DELL powervault 220s storage. > > We already disabled the atime updates and the quotas_account but the gain > > in performance is not too significant. > > > > Any other hints ? > > Look at /proc/cluster/lock_dlm/drop_count > > It's 50000 by default and increasing it could possibly improve things, > or disable it altogether by setting to zero. > e.g. echo "0" >> /proc/cluster/lock_dlm/drop_count > > You need to change this prior to mounting gfs on each node. When > non-zero, GFS/lock_dlm tries to keep the number of locks held locally > below this level which limits the caching gfs can do. When zero, no > limiting is attempted. Additionally, there are performance implications when using JBODs + host-RAID controllers. Basically, each controller's caching has to be disabled (aka "put in cluster mode") in order for most host-RAID controllers to operate properly in a clustered environment. Naturally, disabling the RAID controllers' cache can hurt I/O performance. It might be interesting to test a one node configuration with and without cache disabled and see if there is a significant change in performance with your tests (still using DLM+GFS, of course). Out of curiosity, what tests/benchmarks are you using? -- Lon
