topic Re: 16Tb lun limit windows Ontap 9.3 in ONTAP Discussions

16Tb lun limit windows Ontap 9.3

pippen23 — Wed, 04 Jun 2025 13:55:06 GMT

Hello smart people...I was asked today about creating a lun for windows of 25TB, I know in server 2008 this is the max, but, I am pretty sure windows has increased this in 2012 and 2016. Does anyone know why Netapp has not increased this limit ? I checked it on a system running Ontap 9.3 on a Netapp8200...

Re: 16Tb lun limit windows Ontap 9.3

AlexDawson — Mon, 16 Apr 2018 05:09:31 GMT

In currently shipping versions of ONTAP, the limit for a single file is 16TB. LUNs are stored inside special files inside of the filesystem, and so are subject to this limit.

Rest assured that this feedback is widely received from our customer base, but in many cases alternative options can be implemented to work around this.

Re: 16Tb lun limit windows Ontap 9.3

RR-IT — Mon, 21 May 2018 22:19:09 GMT

This is a ridiculous limitiation in a time where single disk drives are this large.

Re: 16Tb lun limit windows Ontap 9.3

bblairevo — Thu, 29 Nov 2018 15:59:42 GMT

To create a VMWare datastore larger than 16TB are you suggesting using VMFS extents? Does this concatenate them?

Any chance this limitation of 16TB is increased in 9.5?

Thanks

Re: 16Tb lun limit windows Ontap 9.3

AlexDawson — Thu, 29 Nov 2018 23:04:43 GMT

It is not increased in 9.5, no.

Yes, using multiple extents would be one option, or using NFS instead of iSCSI.

Re: 16Tb lun limit windows Ontap 9.3

thibaud_lenik — Wed, 19 Dec 2018 09:52:58 GMT

@AlexDawson wrote:

It is not increased in 9.5, no.

Yes, using multiple extents would be one option, or using NFS instead of iSCSI.

Yes, but No.

One of the killing point for NetApp : Veeam backup & restore with SnapMirror/Vault and Exchange.

If you want to backup & restore Exchange mailboxes using SnapVault / SnapMirror you need to have a single VMFS datastore

Exchange is NOT supported on NFS datastore

If your mailboxes LUNs / VMDK are bigger than 16TB, you need to add extend to your existing datastore

Veeam is not able to restore when using VMFS extents.

So 16TB LUN limitation for Exchange when using Veeam is BIG issue and we have to migrate LUNs to another storage vendor.

How to lose a customer for such a ridiculous limitation...

Re: 16Tb lun limit windows Ontap 9.3

v_chris — Wed, 19 Dec 2018 10:02:17 GMT

And VMFS extend anyway isn't a good practice, it' brings complexity to the SAN management, because of the asymetry between the storage and vSphere informations.

Knowing that MS filesystems support up to 16 exbibytes files ...