Yes, and yes. Use the "gfs_tool sb <device> proto no_lock" command on an unmounted filesystem, and remount. (Obviously, you cannot mount the fs on more than one node after you do this.) Jeff > -----Original Message----- > From: linux-cluster-bounces@xxxxxxxxxx > [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of Vikash > Khatuwala > Sent: Saturday, April 25, 2009 4:26 AM > To: linux clustering > Subject: RE: GFS performance. > > Hi, > > Can I downgrade the lock manage from lock_dlm to no_lock? Do > I need to un-mount the gfs partition before changing? I want > to see if it makes any performance improvements. > > Thanks, > Vikash. > > > At 11:18 AM 21-04-09, Vikash Khatuwala wrote: > >Hi, > > > >I am using Virtuozzo OS visualization which does not have a > single file > >for the entire VM's filesystem. All VMs are simply > sub-directories and > >OS files are stored in a common templates directory which is > sym linked > >to back to the VM's directory, so if an OS file is changed > inside the > >VM then the symlink breaks and a new file is put in the VM's private > >directory. I cant use GFS2 because it is not supported by Virtuozzo. > >All VMs are simply running web/db/ftp. > > > >So this basically means that there are a lot of symbolic > links (small > >files). The GFS has a block size of 4K so I also chose 4K as > my block > >size for my performance testing to asses the worst case > scenario. If I > >change the block size to 256K then the performance > difference between > >ext3 and GFS are minimal. Also when I migrate the VM out > from GFS(RAID5 > >SAS 15K) to ext3(single disk SATA), there is a significant > noticeable > >performance gain! > > > >Below tests are on the same disk set (5 disk RAID5 SAS 15K) with 2 > >partitions, GFS and ext3. > >Results at 4K random reads: > >GFS : about 1500K/s > >ext3 : about 7000K/s > > > >Results at 256K random reads: > >GFS : about 45000K/s > >ext3 : about 50000K/s > > > >Results at 256K sequential reads: > >GFS : over 110,000K/s (my single GB NIC maxes out) > >ext3 : over 110,000K/s (my single GB NIC maxes out) > > > >fio test file as below only rw and blocksize were changed for the 3 > >different scenarios above. > >[random-read1] > >rw=randread > >size=10240m > >directory=/vz/tmp > >ioengine=libaio > >iodepth=16 > >direct=1 > >invalidate=1 > >blocksize=4k > > > >[random-read2] > >rw=randread > >size=10240m > >directory=/vz/tmp > >ioengine=libaio > >iodepth=16 > >direct=1 > >invalidate=1 > >blocksize=4k > > > >Thanks, > >Vikash. > > > > > >At 01:00 AM 21-04-09, Jeff Sturm wrote: > >> > -----Original Message----- > >> > From: linux-cluster-bounces@xxxxxxxxxx > >> > [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of Vikash > >> > Khatuwala > >> > Sent: Monday, April 20, 2009 11:23 AM > >> > To: linux-cluster@xxxxxxxxxx > >> > Subject: GFS performance. > >> > > >> > OS : CentOS 5.2 > >> > FS : GFS > >> > >>Can you easily install CentOS 5.3 and GFS2? GFS2 claims to > have some > >>performance improvements over GFS1. > >> > >> > Now I need to make a decision to go with GFS or not, > clearly at 4 > >> > times less performance we cannot afford it, also it > doesn't sound > >> > right so would like to find out whats wrong. > >> > >>Be careful with benchmarks, as they often do not give you a good > >>indication of real-world performance. > >> > >>Are you more concerned with latency or throughput? Any single read > >>will almost certainly take longer to complete over GFS than EXT3. > >>There's simply more overhead involved with any cluster filesystem. > >>However, that's not to say you're limited as to how many > reads you can > >>execute in parallel. So the overall number of reads you > can perform > >>in a given time interval may not be 4x at all (are you running a > >>parallel > >>benchmark?) > >> > >>Jeff > >> > >> > >>-- > >>Linux-cluster mailing list > >>Linux-cluster@xxxxxxxxxx > >>https://www.redhat.com/mailman/listinfo/linux-cluster > > -- > Linux-cluster mailing list > Linux-cluster@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/linux-cluster > > -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
