Have a look at these pages: http://www.bofh-hunter.com/2008/06/13/3ware-performance-in-centos/ https://bugzilla.redhat.com/show_bug.cgi?id=444759 I'm comparing the default 5.1 64bit kernel with the patched one posted in the bug report (kernel-2.6.18-53.1.21.el5.bz321111.x86_64) and I don't quite see any significant difference in write performance for this command: dd if=/dev/zero of=/logs/test bs=100M count=1000 (100GB of data, written in 100MB blocks) It's a Supermicro server, the motherboard is (according to the stuff painted on the mobo itself) Super X7DBI+, Intel Xeon L5420 with 8 cores total, 3ware 9650SE using the driver from the manufacturer's site. I tested 2 disks in a mirror RAID volume. Results: kernel time speed ====== ==== ====patched 75min 23M/s original 51min 34M/s patched 48min 36M/s original 61min 28M/s -- Florin Andrei http://florin.myip.org/
On Thu, Jun 19, 2008 at 10:55 AM, Florin Andrei <florin at andrei.myip.org> wrote:> Have a look at these pages: > > http://www.bofh-hunter.com/2008/06/13/3ware-performance-in-centos/ > https://bugzilla.redhat.com/show_bug.cgi?id=444759 > > I'm comparing the default 5.1 64bit kernel with the patched one posted in > the bug report (kernel-2.6.18-53.1.21.el5.bz321111.x86_64) and I don't quite > see any significant difference in write performance for this command:That kernel (kernel-2.6.18-53.1.21.el5.bz321111) has nothing to do with the issue you are referring to. It was used by Jim as an *example* of what CentOS can offer... Akemi
On Thu, 19 Jun 2008 at 10:55am, Florin Andrei wrote> Have a look at these pages: > > http://www.bofh-hunter.com/2008/06/13/3ware-performance-in-centos/ > https://bugzilla.redhat.com/show_bug.cgi?id=444759 > > I'm comparing the default 5.1 64bit kernel with the patched one posted in the > bug report (kernel-2.6.18-53.1.21.el5.bz321111.x86_64) and I don't quite see > any significant difference in write performance for this command:That's the wrong patched kernel. You'd need to be using one of the kernels in <http://people.redhat.com/thenzl/kernel/> -- kernel-2.6.18-93.el5.bz444759.x86_64.rpm. I'd be interested in a way of telling from within the OS whether or not MWI is enabled... -- Joshua Baker-LePain QB3 Shared Cluster Sysadmin UCSF
On Thu, Jun 19, 2008 at 1:55 PM, Florin Andrei <florin at andrei.myip.org> wrote:> Have a look at these pages: > > http://www.bofh-hunter.com/2008/06/13/3ware-performance-in-centos/ > https://bugzilla.redhat.com/show_bug.cgi?id=444759 > > I'm comparing the default 5.1 64bit kernel with the patched one posted in > the bug report (kernel-2.6.18-53.1.21.el5.bz321111.x86_64) and I don't quite > see any significant difference in write performance for this command:You are comparing the wrong kernels. The bz321111 kernel was for an NFS related bug and has no 3 impact on 3ware performance. The redhat bug report has the kernels built for 3ware performance. Once 5.2 is rolled out, Johnny Hughes has stated he would consider building a kernel for the 444759 bug. -- During times of universal deceit, telling the truth becomes a revolutionary act. George Orwell