Subclient property "Disable SnapDiff Scan"

Hello @Brommelkamp 

we won’t use SnapDiff if either of the below is true:

If ONTAP >= 9.10.1.
If commcell is installed after 1/Dec/2021.

NetApp has changed the rules around the use of SnapDiff, if customers want to do backup copies (IntelliSnap) or any kind of streaming backup, then snapdiff can no longer be used. This took effect for any new installs after Nov 30th/2021 or the use of ONTAP 9.10.x (currently not fully supported) no matter when the commcell was installed.

Please let me know if this helps.

Thank you for your answer!

Could you explain why a new subclient (again, same NetApp) is trying to use SnapDiff then?

Extract from the log:

SnapDiffV3: FileServer:[<fileserver>] Volume:[<volume>] SnapOne:[CVOP_466_1559_861349] SnapTwo:[CVOP_466_1559_861353] Format:[cifs] Items In Each Iteration [4096]
Falling back to SnapDiff V1. Could not determine NFS node IP address for vserver:[<vserver>] node:[<node>] IPV4:[true] IPV6:[false].
SnapDiff V1 or V2 is not supported for release [9.12.1].

Note that here there is no such subclient property that disables SnapDiff - although apparantly 9.12.1 is unsupported, which seems to fit your comment of saying it won’t work with ONTAP >= 9.10.1

However after adding the additional setting

bUseSnapDiffV2 = false

V1 seems to work again - extract from the log:

SnapDiffStart Not attempting SnapDiff V3 and V2 due to additional setting [bUseSnapDiffV2]
Starting SnapDiff V1. FileServer:[<fileserver>] Volume:[<volume>] SnapOne:[CVOP_466_1559_861385] SnapTwo:[CVOP_466_1559_861386] Format:[cifs] Items In Each Iteration [4096]
File-access-protocol support:[true] version check:[true]
atime support:[true] version check:[true]
End-of-diff support: [true]
Successfully kicked off SnapDiff. Session ID:[276d4dd5-4720-11ee-b427-00a098f97a18:4525831a-30a7-11e9-b142-00a098f97a18]

Regarding the support of SnapDiff in general with ONTAP >= 9.10.1 I found the following:

To use SnapDiff V1 or V2 for ONTAP version 9.10.x or later, contact NetApp support to restore the APIs and also contact Commvault support.

Source: https://documentation.commvault.com/2022e/essential/131717_faster_incremental_backups_for_nas_file_servers_using_netapp_snapdiff.html

In addition, SnapDiff v1 and v2 ZAPIs are available by default in these ONTAP releases:

• ONTAP 9.11.1 P7 and newer
• ONTAP 9.12.1 GA release and newer
• ONTAP 9.13.1 GA release and newer

Source: https://kb.netapp.com/onprem/ontap/dp/SnapDiff/What_SnapDiff_changes_were_made_in_ONTAP_9.10.1

So at least it seems like NetApp would support V1/V2 with our ONTAP Version? (I consider this as confirmed, as it worked fine using the bUseSnapDiffV2 additional setting).

So following that, I still have several questions:

1. Why is SnapDiff working when using the bUseSnapDiffV2 = false Setting?
   1. Judging by the name, I would assume that this simply should stop using V2, but why does it enable V1?
   2. Why does the new subclient not have that “Disable SnapDiff Scan” setting?
   3. Why is that setting apparantly required to make V1 work?
2. As NetApp states, SnapDiff V1/V2/V3 APIs should be active on our ONTAP Version - is it a legal issue that Commvault can’t use them? (Again why does it work with the bUseSnapDiffV2 setting then?)
3. The Commvault Documentation stated that we should contact Commvault support to re-enable SnapDiff - does this work for IntelliSnap/Streaming backups too then?
   Unfortunately I can’t find anything about legal restrictions by NetApp regarding SnapDiff usage.

I would be very happy if you could elaborate on that.

Thanks in advance!