topic Re: Deduplication impact on SnapMirror in ONTAP Discussions

Deduplication impact on SnapMirror

semionkras — Thu, 05 Jun 2025 07:26:38 GMT

Do i need to turn on deduplication on both source and distination volumes or it has no difference at all while replicating with snapmirror ?

Re: Deduplication impact on SnapMirror

adamfox — Tue, 23 Jun 2009 20:03:30 GMT

Depends on the flavor of SnapMirror.

For Volume SnapMirror, you only need to run it on the source as it comes over the wire and is written pre-deduped.

For Qtree SnapMirror, the data is rehydrated on the destination so data would have to be re-deduped on the other side.

Re: Deduplication impact on SnapMirror

semionkras — Tue, 23 Jun 2009 20:16:16 GMT

Pardon my english . let me to rephrase you :

For Volume Snapmirror data transferred compressed so less traffic needed ?

For Qtree same regular traffic transferred without deduplication and i need to enable dedup on both source and destination?

Re: Deduplication impact on SnapMirror

adamfox — Tue, 23 Jun 2009 20:28:50 GMT

Yes. You will typically transfer less traffic with Volume SnapMirror and deduplication because Volume SnapMirror is a physical image transfer so all of the deduplication stays intact across the transfer. Qtree SnapMirror is a logical replication so dedped data is un-deduped, then sent across the wire and is written un-deduped to the destintaion (it stays deduped on the source, of course). So the data would have to re-deduped on the destination in the case of Qtree SnapMirror.

Hope this helps.

Re: Deduplication impact on SnapMirror

semionkras — Tue, 23 Jun 2009 20:45:45 GMT

Thanks Adam for both topics , it was very helpfull for me .

Re: Deduplication impact on SnapMirror

amiller_1 — Thu, 25 Jun 2009 03:24:31 GMT

Just one note that as of 7.3 qtree SnapMirror does support dedup....

http://now.netapp.com/NOW/knowledge/docs/ontap/rel7311/html/ontap/rnote/rel_notes/concept/c_oc_rn_feat73-dp-qsm-dedupe.html

Re: Deduplication impact on SnapMirror

semionkras — Thu, 25 Jun 2009 05:17:00 GMT

Thanks , great news , now i need upgrade mine from 7.2

Re: Deduplication impact on SnapMirror

amiller_1 — Tue, 30 Jun 2009 22:36:27 GMT

If possible though, I'd probably hold off until August (i.e. for the 7.3.2 GD ONTap release).

Re: Deduplication impact on SnapMirror

semionkras — Wed, 01 Jul 2009 05:30:10 GMT

Thanks , i will do this upgrade in august .

Re: Deduplication impact on SnapMirror

highvailsys — Fri, 12 Nov 2010 20:47:10 GMT

Quick question, in 7.3 and later, the online backup guide mentions that metadata is placed at the aggregate level and therefore is not replicated alongside a volume snapmirror. I found this reference in a 7.3 ONline Backup Manual. With this in mind, it sounds like a volume snapmirror rehydrates prior to replication. The reason I say this is that I'm troubleshooting an issue at a customer site where the snapmirror operations is many times larger then the size of the snapshots that should be replicating across.

Any insight on my interpretation or the discrepancy between space consumed in snapshots and what is snapmirrored I'd appreciate it. Both platforms are 7.3.2.

Thanks,

Chris

Re: Deduplication impact on SnapMirror

AVANISHRANJAN — Thu, 26 Jan 2012 05:57:23 GMT

VSM operates on Physical Block Level while QSM and Snapvault operates on Logical Block Level.

So if the Source Volume is de-duped or Compressed(a new feature in Ontap 8.0.1) then please forget to enable the same on the Destination Volumes...

But When we work on the logical block level we need the same on the destination too..