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Posted to users@cloudstack.apache.org by Asai <as...@globalchangemusic.org> on 2016/12/19 03:34:38 UTC
KVM Live VM Snapshots
Greetings,
Is it correct that currently there is no support in Cloudstack for KVM
live VM snapshots? I see that Volume snapshots are available for running
VMs, but that makes me wonder what everyone is doing to get a disaster
recovery backup of a KVM based VM? I did ask this question a few weeks
back, but only one person responded with one solution, and I am really
trying to figure out what the best solutions are here.
Has anybody seen this script?
https://gist.github.com/ringe/334ee88ba5451c8f5732
What is the community's opinion of scripts like this? And also, big
question, if this script is good, why isn't it integrated into Cloudstack?
Thanks,
Asai
Re: KVM Live VM Snapshots
Posted by Andrei Mikhailovsky <an...@arhont.com.INVALID>.
Hi Marco,
While i totally agree with you on the design and resiliance to failures of newly developed apps, I disagree with you on the necessity to have a vm snapshot feature with kvm. and let me explain why.
At the moment, I am running a small acs + kvm + ceph cluster with about a hundred or so vms. Currently, it is a huge problem for me to perform vm snapshots in a reasonably good state, especially if vm has multiple volumes. The problem with ACS implementation (which is not present in openstack for example) is that there is no way I can keep the snapshots on the primary storage (using fast interconnect). The snapshots are copied over a slow link to the nfs secondary storage. It takes ages to perform any operation with the secondary storage due to its silly design (even though I see the reason for its existence in some cases). Now, consider that I have to take a daily snapshot of every volume and some volumes have to snapped on an hourly basis. This totally overloads the network + nfs storage. Imagine that you have to recover a few volumes from snapshots or create new volumes or templates from them while the daily/hourly snapshot cycle is taking place. You will have to wait hours before you get anywhere even on smaller size volumes.
However, when I was testing the XenServer setup with the VM snapshot capability, the snapshot creation and roll back was pretty quick. and it worked for all disk volumes in that vm. I don't remember seeing much network traffic or load on the nfs server either. This feature is a must imho regardless of the application design. Besides, as far as I remember, the KVM have that capability, so, why not implement it within ACS, just like it's done for vmware and xenserver?
Andrei
----- Original Message -----
> From: "Marc-Aurèle Brothier" <ma...@exoscale.ch>
> To: "users" <us...@cloudstack.apache.org>
> Sent: Monday, 19 December, 2016 08:31:26
> Subject: Re: KVM Live VM Snapshots
> Hi Asai,
>
> In my opinion, doing a VM snapshot is making a step in the wrong direction.
> Your applications/system running inside your VMs should be designed to
> handle an OS crash. Then a new VM, freshly installed, should be able to get
> back into your application setup so that you have again an appropriate
> number of healthy nodes.
>
> Marco
>
> On Mon, Dec 19, 2016 at 4:34 AM, Asai <as...@globalchangemusic.org> wrote:
>
>> Greetings,
>>
>> Is it correct that currently there is no support in Cloudstack for KVM
>> live VM snapshots? I see that Volume snapshots are available for running
>> VMs, but that makes me wonder what everyone is doing to get a disaster
>> recovery backup of a KVM based VM? I did ask this question a few weeks
>> back, but only one person responded with one solution, and I am really
>> trying to figure out what the best solutions are here.
>>
>> Has anybody seen this script? https://gist.github.com/ringe/
>> 334ee88ba5451c8f5732
>>
>> What is the community's opinion of scripts like this? And also, big
>> question, if this script is good, why isn't it integrated into Cloudstack?
>>
>> Thanks,
>> Asai
>>
Re: KVM Live VM Snapshots
Posted by Asai <as...@globalchangemusic.org>.
Thanks for the feedback. I guess I need a little more assistance in understanding the correct procedure for disaster recovery.
With XenServer I have my VMs snapshotted then exported to backup weekly. So I guess I've never really used snapshots except to then export the snapshot as a backup VM.
So... How can I do that in Cloudstack with KVM? Or is there a better solution for disaster recovery that doesn't cost $$$?
On December 19, 2016 6:01:02 AM MST, Simon Weller <sw...@ena.com> wrote:
>There is a pending PR awaiting merge that added VM snapshots to ACS for
>KVM.
>
>
>https://github.com/apache/cloudstack/pull/977
>
>
>In regards to why it hasn't been merged, that's a good question. Why
>don't you comment on the PR and ask that question. Community
>involvement is the best way to get features moving forward.
>
>I do agree though with Macro that snapshots are not really designed for
>BCDR purposes.
>
>
>- Si
>
>________________________________
>From: Marc-Aur�le Brothier <ma...@exoscale.ch>
>Sent: Monday, December 19, 2016 2:31 AM
>To: users@cloudstack.apache.org
>Subject: Re: KVM Live VM Snapshots
>
>Hi Asai,
>
>In my opinion, doing a VM snapshot is making a step in the wrong
>direction.
>Your applications/system running inside your VMs should be designed to
>handle an OS crash. Then a new VM, freshly installed, should be able to
>get
>back into your application setup so that you have again an appropriate
>number of healthy nodes.
>
>Marco
>
>On Mon, Dec 19, 2016 at 4:34 AM, Asai <as...@globalchangemusic.org>
>wrote:
>
>> Greetings,
>>
>> Is it correct that currently there is no support in Cloudstack for
>KVM
>> live VM snapshots? I see that Volume snapshots are available for
>running
>> VMs, but that makes me wonder what everyone is doing to get a
>disaster
>> recovery backup of a KVM based VM? I did ask this question a few
>weeks
>> back, but only one person responded with one solution, and I am
>really
>> trying to figure out what the best solutions are here.
>>
>> Has anybody seen this script? https://gist.github.com/ringe/
>[https://assets-cdn.github.com/images/modules/open_graph/github-logo.png]<https://gist.github.com/ringe/>
>
>ringe's gists � GitHub<https://gist.github.com/ringe/>
>gist.github.com
>Maximum users of an application, limit license usage on Windows
>Terminal Server View maximum_users.ps1. # name of procsess we are
>tracking $ limited_process ...
>
>
>
>> 334ee88ba5451c8f5732
>>
>> What is the community's opinion of scripts like this? And also, big
>> question, if this script is good, why isn't it integrated into
>Cloudstack?
>>
>> Thanks,
>> Asai
>>
>>
--
Asai
Re: KVM Live VM Snapshots
Posted by Simon Weller <sw...@ena.com>.
There is a pending PR awaiting merge that added VM snapshots to ACS for KVM.
https://github.com/apache/cloudstack/pull/977
In regards to why it hasn't been merged, that's a good question. Why don't you comment on the PR and ask that question. Community involvement is the best way to get features moving forward.
I do agree though with Macro that snapshots are not really designed for BCDR purposes.
- Si
________________________________
From: Marc-Aurèle Brothier <ma...@exoscale.ch>
Sent: Monday, December 19, 2016 2:31 AM
To: users@cloudstack.apache.org
Subject: Re: KVM Live VM Snapshots
Hi Asai,
In my opinion, doing a VM snapshot is making a step in the wrong direction.
Your applications/system running inside your VMs should be designed to
handle an OS crash. Then a new VM, freshly installed, should be able to get
back into your application setup so that you have again an appropriate
number of healthy nodes.
Marco
On Mon, Dec 19, 2016 at 4:34 AM, Asai <as...@globalchangemusic.org> wrote:
> Greetings,
>
> Is it correct that currently there is no support in Cloudstack for KVM
> live VM snapshots? I see that Volume snapshots are available for running
> VMs, but that makes me wonder what everyone is doing to get a disaster
> recovery backup of a KVM based VM? I did ask this question a few weeks
> back, but only one person responded with one solution, and I am really
> trying to figure out what the best solutions are here.
>
> Has anybody seen this script? https://gist.github.com/ringe/
[https://assets-cdn.github.com/images/modules/open_graph/github-logo.png]<https://gist.github.com/ringe/>
ringe's gists · GitHub<https://gist.github.com/ringe/>
gist.github.com
Maximum users of an application, limit license usage on Windows Terminal Server View maximum_users.ps1. # name of procsess we are tracking $ limited_process ...
> 334ee88ba5451c8f5732
>
> What is the community's opinion of scripts like this? And also, big
> question, if this script is good, why isn't it integrated into Cloudstack?
>
> Thanks,
> Asai
>
>
Re: KVM Live VM Snapshots
Posted by Marc-Aurèle Brothier <ma...@exoscale.ch>.
Hi Asai,
In my opinion, doing a VM snapshot is making a step in the wrong direction.
Your applications/system running inside your VMs should be designed to
handle an OS crash. Then a new VM, freshly installed, should be able to get
back into your application setup so that you have again an appropriate
number of healthy nodes.
Marco
On Mon, Dec 19, 2016 at 4:34 AM, Asai <as...@globalchangemusic.org> wrote:
> Greetings,
>
> Is it correct that currently there is no support in Cloudstack for KVM
> live VM snapshots? I see that Volume snapshots are available for running
> VMs, but that makes me wonder what everyone is doing to get a disaster
> recovery backup of a KVM based VM? I did ask this question a few weeks
> back, but only one person responded with one solution, and I am really
> trying to figure out what the best solutions are here.
>
> Has anybody seen this script? https://gist.github.com/ringe/
> 334ee88ba5451c8f5732
>
> What is the community's opinion of scripts like this? And also, big
> question, if this script is good, why isn't it integrated into Cloudstack?
>
> Thanks,
> Asai
>
>