[SOLVED] Veeam Failed: Understanding disk space with Veeam and VM ?

[velocityg4]

I originally posted this question on Spiceworks. Figured I may as well check here. Also noticed Tom's doesn't have a sub forum for Servers and Server software. It's obviously not part of Tom's Guide either. Not sure if there's yet another forum for IT issues.

I've got a server running VMWare ESXi 6.7.0. Guest OS is Windows Server 2016 standard. I'm new to Veeam and VMWare ESXi. I'm just used to a straight Windows Server without running off a VM. So, this is all different than I expected.

Issue: Veeam Backup is spitting out the error "Processing (VM Name) Error: Skipping VM processing due to insufficient free disk space on datastore (VM Hard Disk)"

I'm aware I can uncheck "Skip VM Processing when free disk space is below 5%"

Background: This is an existing server. I added an NVMe SSD. Then I went into VMWare and added it as additional storage in VMWare for the Windows Server Guest. I set the virtual storage size (VMFS) to fill the entire SSD (actually 1.8TB of 1.82TB).
In Windows I formatted the drive and used the entire virtual drive.
Actual data on the drive is 601GB of 1.79TB.

Questions: Which formatting is the problem for Veeam and the SSD? Real data used is only 601GB on a 2TB SSD. Which is well above the 5% threshold. So, I'm confused where Veeam is trying to toss the snapshots.

Do I need to recreate the VM storage space? This'll be a big hassle. As I'll have to go onsite and take the VM offline. As I don't believe I can remove a virtual drive while the VM is live.

What's the danger of "Skip VM Processing when free disk space is below 5%"? In my mind there's over 50% free. The best I can figure is Veeam wants to place snapshots outside the formatted space on the SSD. Which makes no sense to me.


Edit: Just saw the Prebuilt and Enterprise subforum. If this is better suited there. Then mods please move.

Edit 2: Just found this entry from Veeam about tuning VSphere. I'm guessing this means I need to toast the virtual drive I made then redo it?

• Allocate enough space for snapshots. VMware vSphere 5.x puts the snapshot VMDK on the same datastore with the parent VMDK. If a VM has virtual disks on multiple datastores, each datastore must have enough space to hold the snapshots for their volume. Take into consideration the possibility of running multiple snapshots on a single datastore. According to the best practices, it is strongly recommended to have 10% free space within a datastore for a general use VM, and at least 20% free space within a datastore for a VM with high change rate (SQL server, Exchange server, and others).
  
  Note: This is the default behavior that can be changed as explained in VMware KB Article 1002929.

 

[velocityg4]

Update: Got the answer on another forum. The Datastore needs to be at least 5% larger than all the virtual disks contained in it. So, that snapshots of the VM may be created. Preferably 20% to 25%.