topic Re: Create a snapmirror relationship for DRP between 2 sites in ONTAP Discussions

Create a snapmirror relationship for DRP between 2 sites

Julien_Mos — Wed, 04 Jun 2025 09:41:02 GMT

Hello,

I need to create a relationship between my 2 Netapps . There are on 2 differents sites.

The second site is use for DRP, so I need to replicate all my productions volumes from my main site on the secondary and if it's possible I need to replicate it in real time. Or if it's not in real time, at least the more often.

Can somebody explain me how to do this with the right policy ?

Best,

Re: Create a snapmirror relationship for DRP between 2 sites

ansley_tj — Tue, 13 Feb 2024 14:33:59 GMT

SnapMirrror asynchronous has been validated for RPOs as low as 5 minutes. As RPOs (replication schedules) get lower, you run into a barrier between what your change rate on the volume is vs the amount of bandwidth available to transmit those changes in the replication schedule interval.

The next option is a Sync policy...which has strict networking performance requirements of having an RTT of 10ms or less. Since this is "real-time" replication, delays in gaining acknowledgment from the DR cluster could impact overall application performance.Also, SnapMirror synchronous only replicates manually created or "application created" snapshots. Also, the synchronous DR volume does not represent the "real-time" view of the primary...we only export the what is called a "common snapshot copy" which is created - by default - every 6 hours, but can be created as little as every 5 minutes.

In both cases, your DR "view" of the data is no less than 5 minutes at best.

Re: Create a snapmirror relationship for DRP between 2 sites

ansley_tj — Tue, 13 Feb 2024 22:20:01 GMT

Correction..as little as every 30 minutes. Sorry about that. Got my SnapMirror policies crossed up 😄

Re: Create a snapmirror relationship for DRP between 2 sites

Julien_Mos — Wed, 14 Feb 2024 11:07:49 GMT

hello, thank you for those informations.

Our 2 sites are linked by a fiber channel. So the Sync policy will be great I think.
I didn't understand the part where you are saying
"SnapMirror synchronous only replicates manually created or "application created" snapshots"
snapmirror are not automated ?

Can I asked you a exemple of command to create this kind of snapmirror relationship please ?

Re: Create a snapmirror relationship for DRP between 2 sites

ansley_tj — Thu, 15 Feb 2024 17:04:38 GMT

"application create" snapshots are those that are created via API/CLI and not part of a snapshot automated schedule, or via a snapmirror policy schedule.

Think 3rd party backup/recovery apps and even SnapCenter which is a NetApp external snapshot management tool that coordinates with client-side OS/applications to create consistent snapshots.

Re: Create a snapmirror relationship for DRP between 2 sites

Julien_Mos — Fri, 16 Feb 2024 13:18:15 GMT

So if I setup a "classic" relationship snapmirror, the created snaps will be replicated automatically ?

Re: Create a snapmirror relationship for DRP between 2 sites

ansley_tj — Fri, 16 Feb 2024 14:41:21 GMT

Not sure what you mean by "classic"...are you saying that means SnapMirror asynchronous (as opposed to synchronous)?

If so, then yes, any snapshots created with "snapmirror label" matching one of the rules in your SnapMirror mirror-vault or vault policy will be replicated based on the rules you create.

Re: Create a snapmirror relationship for DRP between 2 sites

Julien_Mos — Mon, 19 Feb 2024 15:17:57 GMT

That's precisely my problem.
My relationship between the 2 netapps seems healthy and functional, however, the snapshots don't copy from the source to the destination and I don't know why?

Is the problem with the snapshot policy?