run ndmpcopy without overwriting files or duplication

Brandon3 — Thu, 04 Dec 2025 02:25:34 GMT

Hello,

I want to run ndmpcopy from one volume to another on the same netapp, but I want to make sure that files that may already exist on the destination netapp are not duplicated and overfill the volume to 100%

Earlier I ran: node run -node node1 ndmpcopy -sa ndmpuser:yMGg5d0LyUG8l1kn -da ndmpuser:yMGg5d0LyUG8l1kn 10.63.107.200:/svm2/vol1 10.63.107.200:/svm2/vol2

But this resulted in the destination netapp being overfilled to 100%. Is there a way to make sure this doesn't happen?

Both source volume had 500GB of storage and it was 66% full, the destination volume is also 500GB and was at 25% full.

Re: run ndmpcopy without overwriting files or duplication

chamfer — Thu, 11 Dec 2025 02:23:51 GMT

Hello @Brandon3,

Unfortunately, ndmpcopy doesn’t do deduplication or file-level checks.... it’s a straight copy operation. If the destination already has data, it won’t reconcile or skip duplicates, so you’ll want to plan around that.

A couple of clarifying questions that will help narrow down the best approach for you:

What NetApp ONTAP platform are you running on (AFF, FAS, or ASA)?
Which ONTAP software version are you currently using? Some features and behaviors differ between releases.
What storage efficiency ratio are you seeing on the destination volume (deduplication, compression, compaction)?
Is the destination volume already serving data to clients, or is it purely a replication target?
Do you need this to be a one-time copy, or an ongoing sync/replication?

With those details, it’ll be easier to recommend whether ndmpcopy is the right tool, or if SnapMirror or XCP might be a better fit for your use case.

NDMP is a protocol designed for backups, and while you can still use it for copy operations you need to understand its limitations. For example, you could have a heap of deduplicated data on your source volume (even 2:1) that is going to your destination volume with either deduplication disabled or even post-process deduplication (e.g. FAS)......... it will fill up.

There is also a great KB article here which discusses the incremental copy feature of ndmpcopy What is the difference between levels 1 to 9 for an incremental copy - NetApp Knowledge Base which depending on your use case could help.

topic run ndmpcopy without overwriting files or duplication in General Discussion

run ndmpcopy without overwriting files or duplication

Re: run ndmpcopy without overwriting files or duplication