On Fri, 13 Jan 2006 21:14 , Tomas Florian <tflorian@telus.net> sent:>Hello, > >I''m having trouble with slow IO performance under Xen 2.0.7 with 2.6 >kernel. I''m running 3 physical machine. I did hdparm -tT in my Dom0 on >both servers and this is what I get:<snip> I would check to make sure your kernels have the right ide drivers builtin or as modules, i''ve seen this type of performance on a few machines and the fix was to double check the kernel config. Adam Wendt IPCoast, Inc. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Here are results from my devel box with an old seagate 20gb hdd. Both results are on the same machine, first one is from inside domU, and second is from dom0. These results are without any scheduling imposed on any domain and with only one domain active on dom0. The domU is a bare bone centos with min services running. A lot of difference in results. [from inside domU] hdparm -tT /dev/sda1 /dev/sda1: Timing cached reads: 896 MB in 2.01 seconds = 445.77 MB/sec Timing buffered disk reads: 54 MB in 3.03 seconds = 17.82 MB/sec [from inside dom0] hdparm -tT /dev/hdb /dev/hdb: Timing cached reads: 932 MB in 2.00 seconds = 466.00 MB/sec Timing buffered disk reads: 68 MB in 3.07 seconds = 22.15 MB/sec On Fri, 13 Jan 2006 22:28:14, Adam Wendt <adam@ipcoast.com> wrote:> > On Fri, 13 Jan 2006 21:14 , Tomas Florian <tflorian@telus.net> sent: > > >Hello, > > > >I''m having trouble with slow IO performance under Xen 2.0.7 with 2.6 > >kernel. I''m running 3 physical machine. I did hdparm -tT in my Dom0 on > >both servers and this is what I get: > > <snip> > > I would check to make sure your kernels have the right ide drivers builtin > or as > modules, i''ve seen this type of performance on a few machines and the fix > was to > double check the kernel config. > > Adam Wendt > IPCoast, Inc. > > > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users >-- regards, Anand _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Thank you so much Adam .... I have recompiled the kernel with the chipset specific support and it works great now. (getting 30 - 35 MB/s like I should be) For anyone who is wondering what I did exactly: - used lspci to find out my exact IDE chipset - edited my kernel config file to include CONFIG_BLK_DEV_SIS5513 = yes CONFIG_BLK_DEV_VIA82CXXX = yes Of course your''s will depend on your chipset. I also ended up upgrading to Xen 3 (why not, if I''m already doing all this work) ... but I doubt that had anything to do with resolving this problem. Tomas Adam Wendt wrote:> On Fri, 13 Jan 2006 21:14 , Tomas Florian <tflorian@telus.net> sent: > > >> Hello, >> >> I''m having trouble with slow IO performance under Xen 2.0.7 with 2.6 >> kernel. I''m running 3 physical machine. I did hdparm -tT in my Dom0 on >> both servers and this is what I get: >> > > <snip> > > I would check to make sure your kernels have the right ide drivers builtin or as > modules, i''ve seen this type of performance on a few machines and the fix was to > double check the kernel config. > > Adam Wendt > IPCoast, Inc. > > > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Anand wrote:> Timing cached reads: 932 MB in 2.00 seconds = 466.00 MB/sec > Timing buffered disk reads: 68 MB in 3.07 seconds = 22.15 MB/secYour system seems a bit sluggish too, doesn''t it? I''m getting 55-60 MB/sec for buffered reads and 1600 for cached. AFAIK, standard modern ATA disks should give you around 50 MB/sec read speed... _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 1/17/06, Molle Bestefich <molle.bestefich@gmail.com> wrote:> > Anand wrote: > > Timing cached reads: 932 MB in 2.00 seconds = 466.00 MB/sec > > Timing buffered disk reads: 68 MB in 3.07 seconds = 22.15 MB/sec > > Your system seems a bit sluggish too, doesn''t it? > I''m getting 55-60 MB/sec for buffered reads and 1600 for cached. > > AFAIK, standard modern ATA disks should give you around 50 MB/sec read > speed... >Yup. However i don''t know what is actually wrong here. This is a standard seagate 20GB and the host kernel is the stock xen 3.0 stable kernel. -- regards, Anand _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users