topic Possible to determine changed content in snapshot? in Network and Storage Protocols

Possible to determine changed content in snapshot?

rcg007talecris — Thu, 05 Jun 2025 07:16:28 GMT

Question - anyone know of a way (API, CLI, other) to determine which files actually have changed nodes from one snapshot to another (or from the base to a snapshot)? Limiting this to one generation only at the moment. Obviously I am looking for something beyond the brute force method of file by file meta data compare between two generations of snapshot.

The base volume is assumed in this case to contain files shared via NFS, CIFS, etc. rather than a block level LUN.

This is not specifically backup related, which would be an obvious follow-up. More of a theoretical "is it possible" kind of thing...

Thanks in advance!

Re: Possible to determine changed content in snapshot?

adamfox — Wed, 24 Mar 2010 23:09:38 GMT

I don't know of a native way of doing this. Snapshots are block based, not file based.

-- Adam Fox

Re: Possible to determine changed content in snapshot?

shaun_flynn — Thu, 25 Mar 2010 20:38:27 GMT

TSM6.1 can do this utilizing the SnapDiff API that NetApp created. So there is some API out there which hopefully more backup apps or ZAPI itself could query in the future.......

Re: Possible to determine changed content in snapshot?

adamfox — Thu, 25 Mar 2010 20:56:04 GMT

I stand corrected. I think I had forgotten about the SnapDiff API call. So it's available in the ONTAP SDK if you want to code to it.

Re: Possible to determine changed content in snapshot?

rcg007talecris — Mon, 29 Mar 2010 16:46:17 GMT

Thanks everyone - exactly the kind of info I was looking for.

Re: Possible to determine changed content in snapshot?

thomas_tomlinson — Mon, 17 May 2010 13:11:38 GMT

Is the snapdiff API call in the current 4.0 SDK? I can't find any reference to it in the 4.0 docs.

Re: Possible to determine changed content in snapshot?

Daniel_Holt — Mon, 11 May 2015 07:17:09 GMT

Hi Guys, just revisiting this option. I'm new to the SDK, can someone explain how this works. Its now 5 years on, is there any other way to get the same solution?