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mvalpreda
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Share VHD across VMs that I can back up with Veeam - VHD sets with one machine?

Post by mvalpreda »

I know this might be a strange place to ask this, but thinking someone might have done something creative....No complaints about Veeam!

Working with a customer that has a 4x SQL servers running as VMs on a single 2016 host. They have set up symlinks on the SQL VMs to point to storage on the physical host. So the D: drive on the SQL1 VM has a folder called data that points to \\host\sqldata\sql1\data, and d:\logs on the host points to \\host\sqldata\sql1\logs\. Same thing on SQL2, SQL3, and SQL4. There is another host with another 3 or 4 SQL VMs doing the exact same thing. Veeam only backs up the data actually in the VHDX, and not referenced through the symlink - as expected.

Want to unravel this mess and get these VMs properly backing up with Veeam like the rest of the VMs on the hosts. Was looking at a shared VHD, but see that Veeam doesn't support that, but rather to use VHD Sets. There is no clustering and probably won't be. Can I set up clustered storage even though it obviously won't be clustered with a single host? When I try and add a VHD Set to a VM, I get the error

The storage where the virtual hard disk is located does not support virtual hard disk sharing.

I assume that is because the VHD is not in c:\clusterstorage\

Putting a VHD for each VM with the data, logs, and backups doesn't appear to be an option. Customer is concerned they won't carve up the space correctly, give too much space to one machine, not enough to another, run out of space on one, etc. Shared storage or complicating the topology with a virtual SAN is more than likely out of the picture.

Open to other suggestions or even someone telling me I'm wasting my time. :)

nmdange
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Re: Share VHD across VMs that I can back up with Veeam - VHD sets with one machine?

Post by nmdange »

VHD Sets require CSVs, so they can't be used on a standalone Hyper-V host. They also require the VMs themselves to be a failover cluster.

I don't really understand what their concern about "carving up space correctly" means. You should always be using dynamic VHDXs, so each VM only takes up allocated space on the host, so I don't really see what the issue is. Also, given that all 4 VMs are running on a single physical server, why not just run a single SQL Server VM?

mvalpreda
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Re: Share VHD across VMs that I can back up with Veeam - VHD sets with one machine?

Post by mvalpreda »

I figured trying to do some sort of trickiness with clustering wasn't going to pan out. Since I can't share a pool of data with multiple guests, I'll push hard to get them to move to VHDX for the SQL servers. That should speed up the SQL guests since they have the network overhead with the symlinks.

I go back and forth with dynamic VHDXs. I'll do fully committed so no one inadvertently over-provisions the storage on the host....and with this shop, that is a definite possibility! We're going through and cleaning up a lot of bad habits.

There are 3x VMs with 128GB for SQL, the memory limit for SQL Standard.....so 3x instead of paying obscene money for SQL Enterprise - at least that is what I have been told. They tend to throw horsepower at any problem.

nmdange
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Re: Share VHD across VMs that I can back up with Veeam - VHD sets with one machine?

Post by nmdange »

The 128GB limit is per instance, not per server, so they could run all 3 instances on a single VM.

mvalpreda
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Re: Share VHD across VMs that I can back up with Veeam - VHD sets with one machine?

Post by mvalpreda »

I'm sure there are a lot of better ways to clean this up.....but some things are better left alone. The devs are a bit touchy.

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