Error with large VM

[cyberswb]

We are a reseller and are evaluating Veeam for a customer.

They have a large Windows fileserver VM with 3 virtual disks, a 60 GB VMDK and two 1 TB VMDKs glued together in Windows as a 2GB logical volume. All VMDKs are thick provisioned.

When running a backup of this VM, the job fails completely with the following error:

CreateSnapshot failed, vmRef "vm-102", timeout "1800000", snName "VEEAM BACKUP TEMPORARY SNAPSHOT", snDescription "Please do not delete this snapshot. It is being used by Veeam Backup.", memory "False", quiesce "False
File <unspecified filename> is larger than the maximum size supported by datastore '<unspecified datastore>

Other VMs in this job run correctly without error. This VM is on a host that is part of a 4 node HA cluster, all connected to an Equallogic iSCSI SAN. The VMFS partition is 7.9 TB (4 x 2 TB extents) and has 3+ TB free. Veeam version is 4.1.1.

[Vitaliy S.]

Hello Shawn,

We already have the similar topic covering the same situation, please have a look: Datastore Block Size Requirements

Hope it helps!

[cyberswb]

It does, I think. We have a 4MB block size and 1 TB disks. 4MB block size has a maximum of 1TB disks and with max size disks we have no room for the overhead.

In this case, the solution is likely to be going to 3 x 750 GB VMDKs replacing the two 1TB VMDKs for a Windows logical volume of roughly the same size.

Am I reading this right?

[Vitaliy S.]

Yes, that's correct. Reducing the virtual disk size will help you to resolve this situation. If you have additional disk space to temporary move VM disk files to another datastore and reformat the old VMFS volume with 8MB block size, this will also allow you to backup that Windows File Server successfully.