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Posted to users@cloudstack.apache.org by Douglas Land <ds...@looprock.com> on 2016/07/06 19:03:06 UTC
Question about migrating local storage datadisks
We use local storage for everything, including datadisks. We need to
migrate these to another host, which docs all seem to say isn’t supported.
I’m confused why we can’t snapshot a datadisk, which, if I understand
correctly, should then get copied to secondary storage, and then bring it
up on another host. I hope I’m just missing something obvious.
RE: Question about migrating local storage datadisks
Posted by Somesh Naidu <So...@citrix.com>.
Yes, as long as the hypervisor host where the VM is running in step #5 does not have access to the storage where the datadisk currently resides.
Regards,
Somesh
-----Original Message-----
From: technopathology@gmail.com [mailto:technopathology@gmail.com] On Behalf Of Douglas Land
Sent: Thursday, July 07, 2016 1:30 AM
To: users@cloudstack.apache.org
Subject: Re: Question about migrating local storage datadisks
So I'm not sure I understood you correctly but the steps as I tries them
were:
1) shut down a VM
2) detach datadisk
3) migrate VM
4) re-attach datadisk??
5) restart the VM
Is that the correct scenario where cloudstack should migrate the datadisk
for me?
On Wed, Jul 6, 2016 at 4:35 PM, Douglas Land <ds...@looprock.com> wrote:
> Thanks Somesh, I'll try just moving the VM and see if it triggers a
> datadisk migration.
>
> Sorry, by 'bring up' I just meant migrate to a new host.
>
>
> On Wednesday, July 6, 2016, Somesh Naidu <So...@citrix.com> wrote:
>
>> First off, for datadisks, you may not explicitly need to move them
>> around. If you detach it from the existing VM and attach it to another VM
>> (essentially the host running that VM) that does not have access to the
>> storage where the datadisk currently resides, then cloudstack will copy the
>> datadisk to a storage accessible to that host.
>>
>> > I’m confused why we can’t snapshot a datadisk, which, if I understand
>> > correctly, should then get copied to secondary storage, and then bring
>> it
>> > up on another host. I hope I’m just missing something obvious.
>>
>> You can snapshot a datadisk and the snapshot will reside on the secondary
>> store, that bit is straight/correct.
>>
>> I do not understand what you mean when you say "bring it up on another
>> host".
>> The part that is not clear is what does "bring it up" mean? Also, what
>> you mean by "host", hypervisor or storage? Do you mean the datadisks are
>> bootable and you want to start them on a different host? If so, know that
>> you can't launch a VM directly off of a snapshot, you’d have to convert it
>> to a template and then launch a VM from it. The VM could be launched on any
>> host - if this is the use-case/scenario you had in mind then yes, you will
>> achieve what you need this way.
>>
>> Regards,
>> Somesh
>>
>>
>> -----Original Message-----
>> From: technopathology@gmail.com [mailto:technopathology@gmail.com] On
>> Behalf Of Douglas Land
>> Sent: Wednesday, July 06, 2016 3:03 PM
>> To: users@cloudstack.apache.org
>> Subject: Question about migrating local storage datadisks
>>
>> We use local storage for everything, including datadisks. We need to
>> migrate these to another host, which docs all seem to say isn’t supported.
>> I’m confused why we can’t snapshot a datadisk, which, if I understand
>> correctly, should then get copied to secondary storage, and then bring it
>> up on another host. I hope I’m just missing something obvious.
>>
>
Re: Question about migrating local storage datadisks
Posted by Douglas Land <ds...@looprock.com>.
So I'm not sure I understood you correctly but the steps as I tries them
were:
1) shut down a VM
2) detach datadisk
3) migrate VM
4) re-attach datadisk??
5) restart the VM
Is that the correct scenario where cloudstack should migrate the datadisk
for me?
On Wed, Jul 6, 2016 at 4:35 PM, Douglas Land <ds...@looprock.com> wrote:
> Thanks Somesh, I'll try just moving the VM and see if it triggers a
> datadisk migration.
>
> Sorry, by 'bring up' I just meant migrate to a new host.
>
>
> On Wednesday, July 6, 2016, Somesh Naidu <So...@citrix.com> wrote:
>
>> First off, for datadisks, you may not explicitly need to move them
>> around. If you detach it from the existing VM and attach it to another VM
>> (essentially the host running that VM) that does not have access to the
>> storage where the datadisk currently resides, then cloudstack will copy the
>> datadisk to a storage accessible to that host.
>>
>> > I’m confused why we can’t snapshot a datadisk, which, if I understand
>> > correctly, should then get copied to secondary storage, and then bring
>> it
>> > up on another host. I hope I’m just missing something obvious.
>>
>> You can snapshot a datadisk and the snapshot will reside on the secondary
>> store, that bit is straight/correct.
>>
>> I do not understand what you mean when you say "bring it up on another
>> host".
>> The part that is not clear is what does "bring it up" mean? Also, what
>> you mean by "host", hypervisor or storage? Do you mean the datadisks are
>> bootable and you want to start them on a different host? If so, know that
>> you can't launch a VM directly off of a snapshot, you’d have to convert it
>> to a template and then launch a VM from it. The VM could be launched on any
>> host - if this is the use-case/scenario you had in mind then yes, you will
>> achieve what you need this way.
>>
>> Regards,
>> Somesh
>>
>>
>> -----Original Message-----
>> From: technopathology@gmail.com [mailto:technopathology@gmail.com] On
>> Behalf Of Douglas Land
>> Sent: Wednesday, July 06, 2016 3:03 PM
>> To: users@cloudstack.apache.org
>> Subject: Question about migrating local storage datadisks
>>
>> We use local storage for everything, including datadisks. We need to
>> migrate these to another host, which docs all seem to say isn’t supported.
>> I’m confused why we can’t snapshot a datadisk, which, if I understand
>> correctly, should then get copied to secondary storage, and then bring it
>> up on another host. I hope I’m just missing something obvious.
>>
>
Re: Question about migrating local storage datadisks
Posted by Douglas Land <ds...@looprock.com>.
Thanks Somesh, I'll try just moving the VM and see if it triggers a
datadisk migration.
Sorry, by 'bring up' I just meant migrate to a new host.
On Wednesday, July 6, 2016, Somesh Naidu <So...@citrix.com> wrote:
> First off, for datadisks, you may not explicitly need to move them around.
> If you detach it from the existing VM and attach it to another VM
> (essentially the host running that VM) that does not have access to the
> storage where the datadisk currently resides, then cloudstack will copy the
> datadisk to a storage accessible to that host.
>
> > I’m confused why we can’t snapshot a datadisk, which, if I understand
> > correctly, should then get copied to secondary storage, and then bring it
> > up on another host. I hope I’m just missing something obvious.
>
> You can snapshot a datadisk and the snapshot will reside on the secondary
> store, that bit is straight/correct.
>
> I do not understand what you mean when you say "bring it up on another
> host".
> The part that is not clear is what does "bring it up" mean? Also, what you
> mean by "host", hypervisor or storage? Do you mean the datadisks are
> bootable and you want to start them on a different host? If so, know that
> you can't launch a VM directly off of a snapshot, you’d have to convert it
> to a template and then launch a VM from it. The VM could be launched on any
> host - if this is the use-case/scenario you had in mind then yes, you will
> achieve what you need this way.
>
> Regards,
> Somesh
>
>
> -----Original Message-----
> From: technopathology@gmail.com <javascript:;> [mailto:
> technopathology@gmail.com <javascript:;>] On Behalf Of Douglas Land
> Sent: Wednesday, July 06, 2016 3:03 PM
> To: users@cloudstack.apache.org <javascript:;>
> Subject: Question about migrating local storage datadisks
>
> We use local storage for everything, including datadisks. We need to
> migrate these to another host, which docs all seem to say isn’t supported.
> I’m confused why we can’t snapshot a datadisk, which, if I understand
> correctly, should then get copied to secondary storage, and then bring it
> up on another host. I hope I’m just missing something obvious.
>
RE: Question about migrating local storage datadisks
Posted by Somesh Naidu <So...@citrix.com>.
First off, for datadisks, you may not explicitly need to move them around. If you detach it from the existing VM and attach it to another VM (essentially the host running that VM) that does not have access to the storage where the datadisk currently resides, then cloudstack will copy the datadisk to a storage accessible to that host.
> I’m confused why we can’t snapshot a datadisk, which, if I understand
> correctly, should then get copied to secondary storage, and then bring it
> up on another host. I hope I’m just missing something obvious.
You can snapshot a datadisk and the snapshot will reside on the secondary store, that bit is straight/correct.
I do not understand what you mean when you say "bring it up on another host".
The part that is not clear is what does "bring it up" mean? Also, what you mean by "host", hypervisor or storage? Do you mean the datadisks are bootable and you want to start them on a different host? If so, know that you can't launch a VM directly off of a snapshot, you’d have to convert it to a template and then launch a VM from it. The VM could be launched on any host - if this is the use-case/scenario you had in mind then yes, you will achieve what you need this way.
Regards,
Somesh
-----Original Message-----
From: technopathology@gmail.com [mailto:technopathology@gmail.com] On Behalf Of Douglas Land
Sent: Wednesday, July 06, 2016 3:03 PM
To: users@cloudstack.apache.org
Subject: Question about migrating local storage datadisks
We use local storage for everything, including datadisks. We need to
migrate these to another host, which docs all seem to say isn’t supported.
I’m confused why we can’t snapshot a datadisk, which, if I understand
correctly, should then get copied to secondary storage, and then bring it
up on another host. I hope I’m just missing something obvious.