Using ubuntu natty narwhal installed today (2011-03-24) I tried to do a
snapshot with the help of libvirt. Here are the results using natty
version of qemu-kvm and libvirt and using presented slowdown packages.
root@koberec:~# time virsh snapshot-create 1
Domain snapshot 1300968929 created
real 4m39.594s
user 0m0.000s
sys 0m0.020s
root@koberec:~# cd /storage/slowsave/
root@koberec:/storage/slowsave# dpkg -l | grep -E 'libvirt|qemu'
ii libvirt-bin 0.8.8-1ubuntu5
the programs for the libvirt library
ii libvirt0 0.8.8-1ubuntu5
library for interfacing with different virtualization systems
ii qemu-common 0.14.0+noroms-0ubuntu3
qemu common functionality (bios, documentation, etc)
ii qemu-kvm 0.14.0+noroms-0ubuntu3
Full virtualization on i386 and amd64 hardware
root@koberec:/storage/slowsave# dpkg -r qemu-common qemu-kvm
root@koberec:/storage/slowsave# dpkg -i
qemu-common_0.12.5+noroms-0ubuntu7.2_all.deb
qemu-kvm_0.12.5+noroms-0ubuntu7.2_amd64.deb
root@koberec:/storage/slowsave# pkill kvm; sleep 5; service libvirt-bin restart
root@koberec:/storage/slowsave# time virsh snapshot-create 1
Domain snapshot 1300969754 created
real 2m22.055s
user 0m0.000s
sys 0m0.010s
root@koberec:/storage/slowsave# qemu-img snapshot -l /storage/debian.qcow2 |
tail -n 1
8 1300969754 57M 2011-03-24 08:29:14 00:03:37.652
root@koberec:/storage/slowsave# virsh console 1
Connected to domain vm
Escape character is ^]
Debian GNU/Linux 5.0 debian ttyS0
debian login: root
Password:
Last login: Thu Mar 24 08:15:18 EDT 2011 on ttyS0
Linux debian 2.6.26-2-amd64 #1 SMP Thu Sep 16 15:56:38 UTC 2010 x86_64
The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
debian:~# free -m
total used free shared buffers cached
Mem: 561 39 521 0 4 16
-/+ buffers/cache: 19 542
Swap: 478 0 478
debian:~#
root@koberec:/storage/slowsave# dd if=/dev/urandom of=/storage/emptyfile bs=1M
count=40
40+0 records in
40+0 records out
41943040 bytes (42 MB) copied, 5.4184 s, 7.7 MB/s
I am not sure if my measurements are relevant to anything in here, but I hope
so.
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/524447
Title:
virsh save is very slow
Status in libvirt virtualization API:
Unknown
Status in QEMU:
Fix Released
Status in “libvirt” package in Ubuntu:
Invalid
Status in “qemu-kvm” package in Ubuntu:
Fix Released
Status in “libvirt” source package in Lucid:
New
Status in “qemu-kvm” source package in Lucid:
In Progress
Status in “libvirt” source package in Maverick:
New
Status in “qemu-kvm” source package in Maverick:
In Progress
Bug description:
==================================
SRU Justification:
1. impact: 'qemu save' is slow
2. how addressed: a patch upstream fixes the case when a file does not
announce when it is ready.
3. patch: see the patch in linked bzr trees
4. TEST CASE: see comment #4 for a specific recipe
5. regression potential: this patch only touches the vm save path.
==================================
As reported here: http://www.redhat.com/archives/libvir-
list/2009-December/msg00203.html
"virsh save" is very slow - it writes the image at around 1MB/sec on
my test system.
(I think I saw a bug report for this issue on Fedora's bugzilla, but I
can't find it now...)
Confirmed under Karmic.
