Network & local disk on same host, live storage migration
Hello. I've been doing some experimentation with oVirt 3.6 and CentOS 7.2 hosts, and I have a few high level questions, related to what I've seen in my testing: 1/ It seems that for a given host, it's impossible to have both a local storage domain and a shared storage domain such as NFS. Is this correct? If so, is adding this capability on the roadmap somewhere? I would really like to have the ability for a single host to simultaneously support both local and network disks. 2/ Does oVirt support any sort of live storage migration functionality? 2.A/ For example, say I have one host (host#1) with two separate NFS storage domains (NFS#1 and NFS#2). In this case, can a VM on host#1 associated with NFS#1 be live migrated to NFS#2 storage? Or can this sort of storage movement only be accomplished by a shutdown of the VM and an export/import/restart workflow? 2.B/ Is the scenario described in 2.A possible across two different hosts that share both NFS storage domains? That is, can a VM guest on host#1/NFS#1 be live migrated to host#2/NFS#2? 3/ Let's says that you setup a host (host#1) with a shared storage domain (NFS#1) and a second host (host#2) with a local storage domain (local#2). If you wanted to move a VM from host#1/NFS#1 to host#2/local#2, how would you most easily accomplish this? All I could come up with is: Add NFS export domain to host#1, turn VM on host#1 off, export VM, add NFS import domain to host#2, import VM, on host#2 onto local#2, turn VM on on host#2? Thanks for your help, -Matthew
On Thursday, April 07, 2016 07:47:59 AM Matthew Bohnsack wrote:
Hello.
I've been doing some experimentation with oVirt 3.6 and CentOS 7.2 hosts, and I have a few high level questions, related to what I've seen in my testing:
1/ It seems that for a given host, it's impossible to have both a local storage domain and a shared storage domain such as NFS. Is this correct? If so, is adding this capability on the roadmap somewhere? I would really like to have the ability for a single host to simultaneously support both local and network disks.
Storage is defined on a data center level, not on a host level, so you are correct you cannot have local storage and shared storage in the same data center.
2/ Does oVirt support any sort of live storage migration functionality?
Yes, if you go to the disks main tab, you can select the disk you want to migrate and click 'move'. This will give you a dialog that allows you to select the target storage domain and profile.
2.A/ For example, say I have one host (host#1) with two separate NFS storage domains (NFS#1 and NFS#2). In this case, can a VM on host#1 associated with NFS#1 be live migrated to NFS#2 storage? Or can this sort of storage movement only be accomplished by a shutdown of the VM and an export/import/restart workflow?
2.B/ Is the scenario described in 2.A possible across two different hosts that share both NFS storage domains? That is, can a VM guest on host#1/NFS#1 be live migrated to host#2/NFS#2?
See above answer, you can live migrate between storage domains, and since storage domains are at a data center level if both hosts are in the same data center, and both storage domains are in the same data center, you can live migrate the storage as well as the VMs. It will be 2 separate operations though.
3/ Let's says that you setup a host (host#1) with a shared storage domain (NFS#1) and a second host (host#2) with a local storage domain (local#2). If you wanted to move a VM from host#1/NFS#1 to host#2/local#2, how would you most easily accomplish this? All I could come up with is: Add NFS export domain to host#1, turn VM on host#1 off, export VM, add NFS import domain to host#2, import VM, on host#2 onto local#2, turn VM on on host#2?
Since these hosts cannot be in the same data center (cannot mix shared and local storage) that is the only option I know of for this particular scenario.
Thanks for your help,
-Matthew
Thanks for your responses. Is gaining the ability to have local and shared storage domains in the same datacenter (and therefore host) on the roadmap? It's most certainly functionality we require in our virtual environment. On Thu, Apr 7, 2016 at 8:44 AM, Alexander Wels <awels@redhat.com> wrote:
On Thursday, April 07, 2016 07:47:59 AM Matthew Bohnsack wrote:
Hello.
I've been doing some experimentation with oVirt 3.6 and CentOS 7.2 hosts, and I have a few high level questions, related to what I've seen in my testing:
1/ It seems that for a given host, it's impossible to have both a local storage domain and a shared storage domain such as NFS. Is this correct? If so, is adding this capability on the roadmap somewhere? I would really like to have the ability for a single host to simultaneously support both local and network disks.
Storage is defined on a data center level, not on a host level, so you are correct you cannot have local storage and shared storage in the same data center.
2/ Does oVirt support any sort of live storage migration functionality?
Yes, if you go to the disks main tab, you can select the disk you want to migrate and click 'move'. This will give you a dialog that allows you to select the target storage domain and profile.
2.A/ For example, say I have one host (host#1) with two separate NFS storage domains (NFS#1 and NFS#2). In this case, can a VM on host#1 associated with NFS#1 be live migrated to NFS#2 storage? Or can this sort of storage movement only be accomplished by a shutdown of the VM and an export/import/restart workflow?
2.B/ Is the scenario described in 2.A possible across two different hosts that share both NFS storage domains? That is, can a VM guest on host#1/NFS#1 be live migrated to host#2/NFS#2?
See above answer, you can live migrate between storage domains, and since storage domains are at a data center level if both hosts are in the same data center, and both storage domains are in the same data center, you can live migrate the storage as well as the VMs. It will be 2 separate operations though.
3/ Let's says that you setup a host (host#1) with a shared storage domain (NFS#1) and a second host (host#2) with a local storage domain (local#2). If you wanted to move a VM from host#1/NFS#1 to host#2/local#2, how would you most easily accomplish this? All I could come up with is: Add NFS export domain to host#1, turn VM on host#1 off, export VM, add NFS import domain to host#2, import VM, on host#2 onto local#2, turn VM on on host#2?
Since these hosts cannot be in the same data center (cannot mix shared and local storage) that is the only option I know of for this particular scenario.
Thanks for your help,
-Matthew
On Thursday, April 07, 2016 11:28:18 AM Matthew Bohnsack wrote:
Thanks for your responses.
Is gaining the ability to have local and shared storage domains in the same datacenter (and therefore host) on the roadmap? It's most certainly functionality we require in our virtual environment.
Honestly I don't know, I don't see it happening any time soon. I haven't heard anyone wanting it. AFAIK most of the effort right now is focused on getting hyper convergence with gluster working correctly and getting all the edge cases to behave. IIRC you can't mix and match local and shared due to only shared having the ability to live migrate while you can't do that with local storage. If it is something you require feel free to open an RFE in bugzilla.
On Thu, Apr 7, 2016 at 8:44 AM, Alexander Wels <awels@redhat.com> wrote:
On Thursday, April 07, 2016 07:47:59 AM Matthew Bohnsack wrote:
Hello.
I've been doing some experimentation with oVirt 3.6 and CentOS 7.2 hosts, and I have a few high level questions, related to what I've seen in my testing:
1/ It seems that for a given host, it's impossible to have both a local storage domain and a shared storage domain such as NFS. Is this correct? If so, is adding this capability on the roadmap somewhere? I would
really
like to have the ability for a single host to simultaneously support both local and network disks.
Storage is defined on a data center level, not on a host level, so you are correct you cannot have local storage and shared storage in the same data center.
2/ Does oVirt support any sort of live storage migration functionality?
Yes, if you go to the disks main tab, you can select the disk you want to migrate and click 'move'. This will give you a dialog that allows you to select the target storage domain and profile.
2.A/ For example, say I have one host (host#1) with two separate NFS
storage domains (NFS#1 and NFS#2). In this case, can a VM on host#1 associated with NFS#1 be live migrated to NFS#2 storage? Or can this
sort
of storage movement only be accomplished by a shutdown of the VM and an export/import/restart workflow?
2.B/ Is the scenario described in 2.A possible across two different
hosts
that share both NFS storage domains? That is, can a VM guest on host#1/NFS#1 be live migrated to host#2/NFS#2?
See above answer, you can live migrate between storage domains, and since storage domains are at a data center level if both hosts are in the same data center, and both storage domains are in the same data center, you can live migrate the storage as well as the VMs. It will be 2 separate operations though.
3/ Let's says that you setup a host (host#1) with a shared storage domain (NFS#1) and a second host (host#2) with a local storage domain (local#2). If you wanted to move a VM from host#1/NFS#1 to host#2/local#2, how would you most easily accomplish this? All I could come up with is: Add NFS export domain to host#1, turn VM on host#1 off, export VM, add NFS import domain to host#2, import VM, on host#2 onto local#2, turn VM on on
host#2?
Since these hosts cannot be in the same data center (cannot mix shared and local storage) that is the only option I know of for this particular scenario.
Thanks for your help,
-Matthew
On Thu, Apr 7, 2016 at 6:28 PM, Matthew Bohnsack <bohnsack@gmail.com> wrote:
Thanks for your responses.
Is gaining the ability to have local and shared storage domains in the same datacenter (and therefore host) on the roadmap? It's most certainly functionality we require in our virtual environment.
I don't think it is on our roadmap at least not for the next release or two. Can you explain why this feature is required? Nir
On Thu, Apr 7, 2016 at 8:44 AM, Alexander Wels <awels@redhat.com> wrote:
On Thursday, April 07, 2016 07:47:59 AM Matthew Bohnsack wrote:
Hello.
I've been doing some experimentation with oVirt 3.6 and CentOS 7.2 hosts, and I have a few high level questions, related to what I've seen in my testing:
1/ It seems that for a given host, it's impossible to have both a local storage domain and a shared storage domain such as NFS. Is this correct? If so, is adding this capability on the roadmap somewhere? I would really like to have the ability for a single host to simultaneously support both local and network disks.
Storage is defined on a data center level, not on a host level, so you are correct you cannot have local storage and shared storage in the same data center.
2/ Does oVirt support any sort of live storage migration functionality?
Yes, if you go to the disks main tab, you can select the disk you want to migrate and click 'move'. This will give you a dialog that allows you to select the target storage domain and profile.
2.A/ For example, say I have one host (host#1) with two separate NFS storage domains (NFS#1 and NFS#2). In this case, can a VM on host#1 associated with NFS#1 be live migrated to NFS#2 storage? Or can this sort of storage movement only be accomplished by a shutdown of the VM and an export/import/restart workflow?
2.B/ Is the scenario described in 2.A possible across two different hosts that share both NFS storage domains? That is, can a VM guest on host#1/NFS#1 be live migrated to host#2/NFS#2?
See above answer, you can live migrate between storage domains, and since storage domains are at a data center level if both hosts are in the same data center, and both storage domains are in the same data center, you can live migrate the storage as well as the VMs. It will be 2 separate operations though.
3/ Let's says that you setup a host (host#1) with a shared storage domain (NFS#1) and a second host (host#2) with a local storage domain (local#2). If you wanted to move a VM from host#1/NFS#1 to host#2/local#2, how would you most easily accomplish this? All I could come up with is: Add NFS export domain to host#1, turn VM on host#1 off, export VM, add NFS import domain to host#2, import VM, on host#2 onto local#2, turn VM on on host#2?
Since these hosts cannot be in the same data center (cannot mix shared and local storage) that is the only option I know of for this particular scenario.
Thanks for your help,
-Matthew
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participants (3)
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Alexander Wels -
Matthew Bohnsack -
Nir Soffer