This is the command used to start one of the affect Linux guests: /usr/bin/kvm -S -M pc-0.12 -enable-kvm -m 512 -smp 1 -name ubuntu -uuid 9de5914b-f448-cb8d-066f-ec51286c80c0 -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/ubuntu.monitor,server,nowait -monitor chardev:monitor -boot c -drive file=/datahauz/kvm/ubuntu.qemu,if=virtio,index=0,boot=on,format=qcow2 -drive if=ide,media=cdrom,index=2 -net nic,macaddr=52:54:00:12:34:56,vlan=0,name=nic.0 -net tap,fd=39,vlan=0,name=tap.0 -chardev pty,id=serial0 -serial chardev:serial0 -parallel none -usb -vnc 127.0.0.1:0 -k en-us -vga cirrus
The SCP file transfers (Linux guest) were tested against both the guest disk as well as guest /dev/shm. Pushing a file through the network stack to /dev/shm was faster than pushing a file from the guest disc to shm. This at least tells us that the guest machine is capable of dealing with greater throughput than the disc. I just wanted to make sure the bottleneck was confined to the disc. FYI, the disc throughput on the Linux guests is poor, but it is at least usable (though not in a production environment). The throughput on Windows guests is 1/10th the speed. For all tests, I verified results by at least two methods. Under Windows guests, I performed file copies to/from guest disc, ftp transfer of large files to the guest disc, and used IOmeter. All three tests provided nearly identical results. ~2MBps R and ~2MBps W +/-500KBps. Under Linux guests, I performed file copies to/from guest disc, scp transfer of large files to/from the guest disc, and ran Bonnie++ (results follow). I also created >2GB files using 'dd' from both /dev/zero and from /dev/mem. Bonnie++ Linux Guest: b...@webtest:~$ time dd if=/dev/zero of=1g bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 67.6536 s, 15.1 MB/s real 1m7.663s user 0m0.080s sys 0m1.510s And again to a raw device without a file system: r...@webtest:~# time dd if=/dev/zero of=/dev/vdb bs=4096 count=400000 400000+0 records in 400000+0 records out 1638400000 bytes (1.6 GB) copied, 66.2002 s, 24.7 MB/s real 1m6.208s user 0m0.070s sys 0m1.750s b...@webtest:~$ bonnie++ Writing with putc()...done Writing intelligently...done Rewriting...done Reading with getc()...done Reading intelligently...done start 'em...done...done...done... Create files in sequential order...done. Stat files in sequential order...done. Delete files in sequential order...done. Create files in random order...done. Stat files in random order...done. Delete files in random order...done. Version 1.03c ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP webtest 1G 12754 17 11505 2 18583 3 65015 93 500392 53 +++++ +++ ------Sequential Create------ --------Random Create-------- -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ webtest,1G,12754,17,11505,2,18583,3,65015,93,500392,53,+++++,+++,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++ Linux Host: b...@octillion:~$ time dd if=/dev/zero of=1g bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 5.2139 s, 196 MB/s real 0m5.412s user 0m0.080s sys 0m2.800s b...@octillion:~$ bonnie++ Writing a byte at a time...done Writing intelligently...done done Reading a byte at a time...done Reading intelligently...done start 'em...done...done...done...done...done... Create files in sequential order...done. Stat files in sequential order...done. Delete files in sequential order...done. Create files in random order...done. Stat files in random order...done. Delete files in random order...done. Version 1.96 ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP octillion 10G 161 97 76547 18 42493 12 1976 96 114159 10 262.1 3 Latency 147ms 4926ms 16159ms 21546us 176ms 198ms Version 1.96 ------Sequential Create------ --------Random Create-------- octillion -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 15145 28 +++++ +++ 22692 29 18729 30 +++++ +++ 25217 30 Latency 695us 749us 577us 728us 60us 131us 1.96,1.96,octillion,1,1269961838,10G,,161,97,76547,18,42493,12,1976,96,114159,10,262.1,3,16,,,,,15145,28,+++++,+++,22692,29,18729,30,+++++,+++,25217,30,147ms,4926ms,16159ms,21546us,176ms,198ms,695us,749us,577us,728us,60us,131us Keep in mind, Linux guest disc performance is 10x better than the Windows guest disc performance. I know the results are a bit scattered as I don't have the ability right now, to do raw write tests to my raid, but either way, all real world disc tests in the guests are consistent, regardless of the host disc (with the exception of /dev/shm). In summary, all reported tests, have been run on the same hardware and under similar conditions (as similar as is possible.) To test this, perhaps someone else could just try to install a Windows XP guest. My install took most of a day to complete, on a quad core 2.4GHz, 5GB RAM system, on top of several rather large raids. Both host raids are mdraid0 and mdraid5 and both have LVM on top. Have tested with identical results to a single SATA2 7500RPM disc. -- Slow disk IO for all guests with all disc modes and types. https://bugs.launchpad.net/bugs/550409 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to libvirt in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs