[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] Difference performances between HVM and PV guest in hard disc reading
On Sun, May 24, 2009 at 7:25 PM, <helicoterus-elih@xxxxxxxx> wrote: > > I perform some tests to get hard disc performance differences between HVM > domU and a paravirtualized one (both Debian Lenny). first of all, make sure you do NOT use file:/ in domU config. At least use tap:aio: > I used hdparm ( option -t and -T) to test cache of disc and disc sequential > read. > Syntax is: > hdparm -t|-T /dev/hda1 > > hdparm -t for hvm returns about 30 MB/sec, wheras hdparm -t for PV return > about 180 MB/sec. This is normal. HVM by default should have MUCH lower disk throughput. That's why HVM domUs need PV drivers for both Linux (included by default on RHEL/Centos 5.3, not available yet for newer kernels) and Windows (like GPLPV). > hdparm -T for hvm returns about 1247 MB/sec, wheras hdparm -T for PV return > about 1183 MB/sec. -T is cached result. Repeat this several times and you should find similar output for both PV and HVM. -- Fajar _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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