I recently migrated my windows machines to a dedicated cloudmin server running CentOs as host.
I found that my windowsxp and windows 2003 machines were terribly slow/lagged. Interestingly my windows 2008 machines were running fine.
After days of troubleshooting, I did a lookup on the running processes of the qemu-kvm and found out that cloudmin, when launching the vm, did not include the necessary parameters to enable the writeback disk cache.
As a quick solution, what I did was I manually launched my vm.
/usr/libexec/qemu-kvm -name WindowsXPMachine.prj -m 3072 -drive index=0,media=disk,file=/virtualmachines/WindowsXPMachine.img,cache=writeback,if=ide -boot c -net tap,vlan=0,script=/virtualmachines/WindowsXPMachine-eth0.sh -net nic,vlan=0,macaddr=00:07:e9:a0:f0:19,model=rtl8139 -vnc :19 -usbdevice tablet -monitor tcp:127.0.0.1:40010,server,nowait -smp 4
Then I used the option in cloudmin to “refresh the status of the machine”, and it came up as alive machine.
And that solved the problem. The windows xp machine is now lightening fast!
Now my question is, how can I enable writeback cache in the cloudmin? Or if there is no such feature, where can I amend the command line arguments/launching script that is used by Cloudmin while launching a vm?
This way I can retain the disk cache feature by simply using the ‘Startup System’ link, rather than manually launching the machine from console.