I still have a problem with the "Live Snapshot" feature of QEMU .... and before migrating to XEN, VMware or something similare, a quick post here:
OS: Ubuntu Natty 64bit
First, i'm starting my KVM Machine with an image like this:
qemu-img create -f qcow2 -o backing_file=<NameOfBaseImage> <Snapshotname>
If i stop the KVM Machine later, and i commit <Snapshotname> into <NameOfBaseImage>, all the new changes are in the <NameOfBaseImage>.
That would be ok.
---
The Problem:
Actually i'm trying to create "live snapshots" periodically while the machine is running, like this (host2Qemu is just a special function of mine (it works), to send a string to qemu-monitor).
My idea is, to commit them one by one afterwards, when the KVM Machine is down into the BaseImage.
So, the Snapshots are beeing written, and everytime i call that function new data is beeing written to the new "alllocated" snapshot.
BUT, committing of that live-snapshots fails, and i've no idea why ?!
I would commit it like that: qemu-img commit -f qcow2 <Snapshot, with KVM was started first> qemu-img commit -f qcow2 <Snapshot1, newer>
qemu-img commit -f qcow2 <Snapshot1, more new> ... and so on.
So in that constellation, only changes from the Snapshot, with KVM was started are in the Base-Image.
And another question: I have a Windows XP Guest also in KVM, but the write performance into the (qcow2 Image) (scp, rsync, e.g) Guest seems to be pretty poor - Are there any hints or is there a special Parameter to avoid this?
The write Performance to a Linux Guest with a similar configuration and also qcow2 seems to very close to the "native" Performance.
Thanks. Robert
[Prev in Thread]
Current Thread
[Next in Thread]
[Qemu-stable] QEMU Live Snapshots / Commiting,
Robert P<=