topic iSCSI lun limits in Windows Server and in SnapDrive for Windows in ONTAP Hardware

iSCSI lun limits in Windows Server and in SnapDrive for Windows

Tas — Wed, 04 Jun 2025 13:25:40 GMT

I understand that most folks these days, are going the virtual route. However, we still have physical systems, especially Windows servers, which we need to provision iSCSI storage to. Unfortunately, 16TB is no longer adequate, we need to provision more.

Trying to find a solution, I came up with the following:

Windows Storage Spaces do not support iSCSI luns in Windows, or in SnapDrive/Windows

Larger luns than 16TB are not supported in Windows, or in SnapDrive/Windows

Dynamic disks support RAID in Windows, but not in SnapDrive/Windows, can you say unquiesced software RAID snapshots?

Could not find any supported LVM for Windows in SnapDrive IMT.

So what gives? Can someone from Netapp shed some light on this?

Re: iSCSI lun limits in Windows Server and in SnapDrive for Windows

AlexDawson — Tue, 14 Aug 2018 06:02:44 GMT

The 16TB LUN size limit is due to the maximum file size supportable by WAFL. As you say - inconsistent snapshots of RAID LUNs don't sound fun, but if you're running OS based data protection, that would be an option.

I've looked into this issue myself, and the understanding based on customer feedback is that this is not a common obstacle (though I have lost one deal because of it..)

In many cases, SMB3 with continuous availability is suitable (HyperV, Microsoft SQL), and that supports much larger sizes. The customer I had an issue with was using Perforce for SCM and for political reasons was not able to move to Linux.