From: Jagane Sundar <jagane@sundar.org>
To: "dlaor@redhat.com" <dlaor@redhat.com>
Cc: Jes Sorensen <Jes.Sorensen@redhat.com>,
Kevin Wolf <kwolf@redhat.com>,
Anthony Liguori <aliguori@us.ibm.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>, Avi Kivity <avi@redhat.com>,
Stefan Hajnoczi <stefan.hajnoczi@uk.ibm.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [RFC] live snapshot, live merge, live block migration
Date: Sun, 15 May 2011 14:38:26 -0700 [thread overview]
Message-ID: <4DD047D2.2020201@sundar.org> (raw)
In-Reply-To: <4DD04231.9010501@redhat.com>
Hello Dor,
> One important advantage of live snapshot over live backup is support of
> multiple (consecutive) live snapshots while there can be only a single
> live backup at one time.
>
> This is why I tend to think that although live backup carry some benefit
> (no merge required), the live snapshot + live merge are more robust
> mechanism.
>
The two things that concern me regarding the
live snapshot/live merge approach are:
1. Performance considerations of having
multiple active snapshots?
2. Robustness of this solution in the face of
errors in the disk, etc. If any one of the snapshot
files were to get corrupted, the whole VM is
adversely impacted.
The primary goal of Livebackup architecture was to have zero
performance impact on the running VM.
Livebackup impacts performance of the VM only when the
backup client connects to qemu to transfer the modified
blocks over, which should be, say 15 minutes a day, for a
daily backup schedule VM.
One useful thing to do is to evaluate the important use cases
for this technology, and then decide which approach makes
most sense. As an example, let me state this use case:
- A IaaS cloud, where VMs are always on, running off of a local
disk, and need to be backed up once a day or so.
Can you list some of the other use cases that live snapshot and
live merge were designed to solve. Perhaps we can put up a
single wiki page that describes all of these proposals.
Thanks,
Jagane
WARNING: multiple messages have this Message-ID (diff)
From: Jagane Sundar <jagane@sundar.org>
To: "dlaor@redhat.com" <dlaor@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Anthony Liguori <aliguori@us.ibm.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Jes Sorensen <Jes.Sorensen@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>, Avi Kivity <avi@redhat.com>,
Stefan Hajnoczi <stefan.hajnoczi@uk.ibm.com>
Subject: Re: [Qemu-devel] [RFC] live snapshot, live merge, live block migration
Date: Sun, 15 May 2011 14:38:26 -0700 [thread overview]
Message-ID: <4DD047D2.2020201@sundar.org> (raw)
In-Reply-To: <4DD04231.9010501@redhat.com>
Hello Dor,
> One important advantage of live snapshot over live backup is support of
> multiple (consecutive) live snapshots while there can be only a single
> live backup at one time.
>
> This is why I tend to think that although live backup carry some benefit
> (no merge required), the live snapshot + live merge are more robust
> mechanism.
>
The two things that concern me regarding the
live snapshot/live merge approach are:
1. Performance considerations of having
multiple active snapshots?
2. Robustness of this solution in the face of
errors in the disk, etc. If any one of the snapshot
files were to get corrupted, the whole VM is
adversely impacted.
The primary goal of Livebackup architecture was to have zero
performance impact on the running VM.
Livebackup impacts performance of the VM only when the
backup client connects to qemu to transfer the modified
blocks over, which should be, say 15 minutes a day, for a
daily backup schedule VM.
One useful thing to do is to evaluate the important use cases
for this technology, and then decide which approach makes
most sense. As an example, let me state this use case:
- A IaaS cloud, where VMs are always on, running off of a local
disk, and need to be backed up once a day or so.
Can you list some of the other use cases that live snapshot and
live merge were designed to solve. Perhaps we can put up a
single wiki page that describes all of these proposals.
Thanks,
Jagane
next prev parent reply other threads:[~2011-05-15 21:38 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-09 13:40 [Qemu-devel] [RFC] live snapshot, live merge, live block migration Dor Laor
2011-05-09 15:23 ` Anthony Liguori
2011-05-09 20:58 ` Dor Laor
2011-05-12 14:18 ` Marcelo Tosatti
2011-05-12 15:37 ` Jes Sorensen
2011-05-10 14:13 ` Marcelo Tosatti
2011-05-12 15:33 ` Jes Sorensen
2011-05-13 3:16 ` Jagane Sundar
2011-05-15 21:14 ` Dor Laor
2011-05-15 21:38 ` Jagane Sundar [this message]
2011-05-15 21:38 ` Jagane Sundar
2011-05-16 7:53 ` Dor Laor
2011-05-16 7:53 ` [Qemu-devel] " Dor Laor
2011-05-16 8:23 ` Jagane Sundar
2011-05-16 8:23 ` [Qemu-devel] " Jagane Sundar
2011-05-17 22:53 ` Dor Laor
2011-05-17 22:53 ` [Qemu-devel] " Dor Laor
2011-05-18 15:49 ` Jagane Sundar
2011-05-18 15:49 ` Jagane Sundar
2011-05-20 12:19 ` Stefan Hajnoczi
2011-05-20 12:39 ` Jes Sorensen
2011-05-20 12:49 ` Stefan Hajnoczi
2011-05-20 12:56 ` Jes Sorensen
2011-05-22 9:52 ` Dor Laor
2011-05-23 13:02 ` Stefan Hajnoczi
2011-05-27 16:46 ` Stefan Hajnoczi
2011-05-27 17:16 ` Jagane Sundar
2011-05-23 5:42 ` Jagane Sundar
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