@olivierlambert said in XO to manage KVM?:

Again, I don't see any problem to use disk controller passthrough for your filer, you won't lose any perfs and you'll have a good isolation.
The rest of the available disks will be used as local storage for the other VMs.

Could you please confirm whether is it the controller or the disks that need to be passthrough? If it's the controller it means you need 2 controllers in the server.

@olivierlambert said in XO to manage KVM?:

(installing NFS in the dom0).

Apologies for my ignorance, because I never tried. Doesn't it create problems to update XCP-ng?

@Biggen said in XO to manage KVM?:

Actually, its still the way I'd do a massive file server. I don't think a 20TB file server needs virtualization. But that's my opinion.

It depends on the use case. Sometimes it's easier to manage the applications isolated in VMs. Even the file level backup software can run in a VM and access the files via NFS share.

@olivierlambert said in XO to manage KVM?:

The message isn't clear because I think we are fundamentally seeing virtualization differently

I guess so. I understand when you look purely on virtualisation Xen and KVM will be similar in a sense. You have a host for the VMs and that's it. There is no "outside". The whole purpose of that physical server is hosting VMs.

I'm having a physical view of a server where a SME can only afford a single server. In that scenario, you are installing softwares to address different necessities. In that scenario, KVM is "just another software" that is addressing the need to host a few VMs whilst NFS/SMB will be serving files, and a webserver will be running webapps, etc. Think on the lines of ClearOS or UnRAID.

@Biggen said in XO to manage KVM?:

Sounds like KVM would be a better solution for you since you want a file server bare metal AND a hypervisor solution wrapped into one.

Indeed, that's why I said XCP-ng wouldn't be a good fit, but XO would be a great addition to manage the virtualisation side of this solution.

And the use case is much wider if you think about larger companies and hosting providers running heterogeneous hosts with both Xen and KVM. I'm pretty sure there are plenty of hosting companies running both Xen and KVM on their DCs.

@olivierlambert said in XO to manage KVM?:

It's the exact same thing for KVM. Any virtualization platform is not "meant" to be a big filer. Period.

I don't know why, but it seems I'm not being able to get my message across. I don't want to run the file server "inside" the virtualisation solution. For my use case the main difference between KVM and Xen is that I can run the file server and KVM side-by-side both using separate local storage. Whilst on Xen I can't do that because I can't install the file server on bare metal.

Thank you @stormi for raising the technical challenges of that implementation and I would say that the main benefit is extending the excellent tool that is XO to the expanding user base of KVM. Just think about all the KVM shops or heterogeneous datacentres that would be able to use XO.

Yes, indeed it's a big strategical change with technical and financial implications, but XO could be an alternative to CloudStack or oVirt.

@olivierlambert said in XO to manage KVM?:

My first answer is "I wouldn't" because it's not meant for that

And that brings me back to my OP where I said XCP-ng was not a good fit for that use case.

On the other hand, you can install the file server on bare metal and have KVM handling the virtualisation side. Two complete different solutions working side-by-side. The piece missing in that overall solution is XO to manage the virtualisation.

Another upside of having XO extended to manage KVM hosts is the possibility of having XO managing a heterogeneous datacentre with both Xen and KVM hosts, similarly to CloudStack and oVirt.

Apologies if I was not clear, but you misunderstood what I said.

Let me try to put as a simple question. How would you setup a 20TB fileserver on XCP-ng?

I can't see other solution than setup NFS/SMB on a VM and attach a disk for storage, but as discussed above this solution has 2 issues: (1) the 2TB limit on VDIs and (2) serving the files stored in a file (VDI) instead of directly from the filesystem would give you poor performance.

These problems could probably be overcome by using disk passthrough but this solution has other implications. For instance, backups.

I would appreciate if you have another solution that I may be missing.

@olivierlambert said in XO to manage KVM?:

what do you need? In simple words.

As I said above:

@beagle said in XO to manage KVM?:

I'm looking for a 1 server solution for SMEs where file storage and VMs can be managed on the same server

@olivierlambert said in XO to manage KVM?:

I don't really understand what you meant with file based storage

I mean files are stored in VDI files on top of the filesystem.

On a KVM installation, you may have NFS/SMB installed directly on the host OS and storing files directly on the filesystem whilst VM disks may be stored as files (i.e. raw, VDI, QCOW2, etc) or LVM.

Please correct me if I'm wrong but on Xen you cannot install anything directly on the host and serve the files directly from the file system because everything run on VMs including DOM0. You need to store them in disks plugged into VMs and those disks are stored as files in the filesystem (VDI, QCOW2). So it means you have an additional layer that would affect your performance.

@olivierlambert said in XO to manage KVM?:

If the disk size is the only issue, there is some workarounds. Eg using SMAPIv3 were disk size won't be limited.

As I mentioned above indeed there are workarounds (e.g. disk passthrough) but it has its drawbacks.

I imagine SMAPIv3 won't have the VDI file size limitations giving it supports QCOW2, but it would still be a file based storage. I don't know all SMAPIv3 features, so please feel free to correct me if I'm wrong.

The issue is finding a solution to run a file server alongside other VMs without affecting its performance and I'm more than happy to hear your suggestions.

Hi,

I guess this is a bit of philosophical question but are there plans to extend Xen Orchestra to manage KVM as well?

I'm looking for a 1 server solution for SMEs where file storage and VMs can be managed on the same server but XCP-ng doesn't seem to be a good fit. Although it's possible to create a VM to work as a file server (SMB/NFS) the VDI has a 2TB limit and the storage would be file based which would affect its performance. Using disk passthrough is another alternative but it brings another set of complications (e.g. backups, etc)

In a KVM solution, there would be a base system running SMB/NFS and KVM, and XO would be managing the VMs (i.e. network, backups, etc).

FreeNAS may be an alternative in the future but it's virtualisation platform Behyve is not as mature as Xen and KVM.

Someone may mention Proxmox but it is not as polished as a solution as XO.

Apologies if this subject was discussed in the past, but I couldn't find anything in my searches.

I believe this script works for CentOS 7:

https://github.com/ronivay/XenOrchestraInstallerUpdater