@scottalanmiller said in Reconsidering ProxMox:

@stacksofplates said in Reconsidering ProxMox:

@stacksofplates said in Reconsidering ProxMox:

@scottalanmiller said in Reconsidering ProxMox:

@stacksofplates said in Reconsidering ProxMox:

After all of this, I still don't get the use case for LVM backed VMs. Other than possibly, possibly a super IO heavy database. Even then, it's questionable.

That's roughly it, and yes, it remains questionable at the best of times.

In the cases where you need LVM fat, you almost certainly also need to avoid LVM because that itty bitty overhead is still too much.

Preallocated qcow2 images are 99% as fast as LVM volumes. Even with just preallocating just the metadata I've had almost native disk write speeds. You lose all of the advantages of qcow2 like libguestfs, the qemu agent, internal and external snapshots, etc.

that said, no idea how the eff you do that with ProxMox. That was just KVM.

It's the default actually. We use Qcow2 on LVM-Thin mostly.

I meant the preallocation. I'd be surprised if they expose that because you can either fully preallocate and zero out the blocks, preallocate and just mark the beginning and end, or just preallocate the metadata.

@stacksofplates said in Reconsidering ProxMox:

@scottalanmiller said in Reconsidering ProxMox:

@stacksofplates said in Reconsidering ProxMox:

After all of this, I still don't get the use case for LVM backed VMs. Other than possibly, possibly a super IO heavy database. Even then, it's questionable.

That's roughly it, and yes, it remains questionable at the best of times.

In the cases where you need LVM fat, you almost certainly also need to avoid LVM because that itty bitty overhead is still too much.

Preallocated qcow2 images are 99% as fast as LVM volumes. Even with just preallocating just the metadata I've had almost native disk write speeds. You lose all of the advantages of qcow2 like libguestfs, the qemu agent, internal and external snapshots, etc.

that said, no idea how the eff you do that with ProxMox. That was just KVM.

@scottalanmiller said in Reconsidering ProxMox:

@stacksofplates said in Reconsidering ProxMox:

After all of this, I still don't get the use case for LVM backed VMs. Other than possibly, possibly a super IO heavy database. Even then, it's questionable.

That's roughly it, and yes, it remains questionable at the best of times.

In the cases where you need LVM fat, you almost certainly also need to avoid LVM because that itty bitty overhead is still too much.

Preallocated qcow2 images are 99% as fast as LVM volumes. Even with just preallocating just the metadata I've had almost native disk write speeds. You lose all of the advantages of qcow2 like libguestfs, the qemu agent, internal and external snapshots, etc.

After all of this, I still don't get the use case for LVM backed VMs. Other than possibly, possibly a super IO heavy database. Even then, it's questionable.

@VoIP_n00b said in Reconsidering ProxMox:

@scottalanmiller said in Reconsidering ProxMox:

We do, shouldn't, but we do because customers don't want to pay for better backups.

I was referring to this ^ Snapshots are not a backup, just like RAID is not a backup.

If I snapshot a VM and copy the snapshot off somewhere else it's a backup.

@VoIP_n00b said in Reconsidering ProxMox:

@scottalanmiller said in Reconsidering ProxMox:

Yeah, just for some reason in that table it shows that you can't. My guess is that it is a typo, but I've not tested it so I can't confirm.

It's defiantly not a typo. I am the member of a proxmox user group, and someone just did a install with LVM and everything related to snapshots was grayed out. Then we figured out it was LVM and not LVM-thin. So regardless if it's "all the same" it matters to proxmox.

Why is each VM getting a volume? Just use qcow2 files. I don't get the point to doing it that way.

@scottalanmiller said in Reconsidering ProxMox:

@stacksofplates said in Reconsidering ProxMox:

@VoIP_n00b said in Reconsidering ProxMox:

@scottalanmiller said in Reconsidering ProxMox:

You definitely can. We use that as the backing to our main backup tools on LVM.

Then your using LVM-thin. Maybe that's just a subset of LVM?

You can snapshot thick provisioned volumes also.

Yeah, just for some reason in that table it shows that you can't. My guess is that it is a typo, but I've not tested it so I can't confirm.

It's been a few years since I've done that. But I'm pretty sure you can (on normal systems I have no idea with ProxMox).

@VoIP_n00b said in Reconsidering ProxMox:

@scottalanmiller said in Reconsidering ProxMox:

You definitely can. We use that as the backing to our main backup tools on LVM.

Then your using LVM-thin. Maybe that's just a subset of LVM?

You can snapshot thick provisioned volumes also.

@VoIP_n00b said in Reconsidering ProxMox:

@stacksofplates You can't take snapshots on LVM. https://pve.proxmox.com/wiki/Storage

You snapshot it through the hypervisor? Why would you do it that way?

@VoIP_n00b said in Reconsidering ProxMox:

@scottalanmiller said in Reconsidering ProxMox:

LVM is what we use.

So you don't take snapshots?

? You can take snapshots without ZFS?