<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=koi8-r"> <META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7650.28"> <TITLE>Disk perfomance</TITLE> </HEAD> <BODY> <!-- Converted from text/plain format --> <P><FONT SIZE=2>Hi there!<BR> <BR> I''ve made some perfomance tests on Fedora Core 6. It seems that there are some troubles with reading from disk through buffers:<BR> <BR> ===============================================================<BR> Dom0:<BR> ==========<BR> hdparm -tT /dev/cciss/c0d0<BR> <BR> Timing cached reads: 2800Mb in 2.00 seconds = 1400.41 Mb/sec<BR> Timing buffered disk reads: 218 Mb in 3.00 seconds = 72.56 Mb/sec<BR> <BR> hdparm -t --direct /dev/cciss/c0d0<BR> <BR> Timing O_DIRECT disk reads: 216 Mb in 3.01 seconds = 71.84 Mb/sec<BR> ==========<BR> <BR> Guest1:<BR> ==========<BR> hdparm -tT /dev/xvda<BR> Timing cached reads: 2788Mb in 2.00 seconds = 1392.98 Mb/sec<BR> Timing buffered disk reads: 72 Mb in 3.07 seconds = 23.44 Mb/sec<BR> <BR> hdparm -t --direct /dev/xvda<BR> <BR> Timing O_DIRECT disk reads: 240 Mb in 3.00 seconds = 79.97 Mb/sec<BR> ===============================================================<BR> <BR> <BR> <BR> <BR> ---<BR> With best regards,<BR> RHCE, Avramenko Andrew<BR> JSC R-Style. Technical support. DIT.<BR> <BR> </FONT> </P> </BODY> </HTML>