replication between different versions of DOT

[nsitps1976]

Can I just check that you can replicate between different versions of DataONTAP?

For example between FAS2050 which can run DOT8.0 and a FAS2020 which runs DOT7.3

[erick_moore · Accepted solution]

You can do it with qtree SnapMirror.  There are limitiations with volume SnapMirror since it replicates the volume metadata.  Also, I don't think the 2050 supports OnTap 8.

Thanks,

E-

[pascalduk]

For volume snapmirror the destination filer needs to be on the same or a higher Ontap version as the source filer.

From the FAS20x0 series only the FAS2040 supports ontap 8.

[nsitps1976]

My mistake, I did mean the 2040.

So I would want to do volume replication from a 2040 (dot8) to a 2020 (dot7.3) - Which from what you are saying this can not be done unless the 2040 is downgraded to dot7.3????? 

[erick_moore]

You CAN do it if you use QSM (QTree SnapMirror) instead of VSM (Volume SnapMirror).  As an example, lets say you have a LUN in the root of a Flexvol on a system running 8.0, 7-Mode.  You want to SM that LUN to a system running 7.3.3.  You cannot use VSM since 7.3.3 does not know about the volume structure in a system running a higher OnTap release.  In this case you would need to move your LUN to a Qtree (which can be done non-disruptively), and then you could use QSM to mirror the data from the OnTap 8, 7-Mode system to the 7.3.3 system.  The reason for this is QSM is replicating only files (a LUN in this case) whereas VSM replicates the entire volume including metadata.

E-

[nsitps1976]

So you can create a SAN LUN used for VMware VMs within a qtree?

[erick_moore]

You absolutely can do that.  If you already have LUNs presented to ESX/vSphere you can easily move those LUNs into qtree's on the fly, and then use QSM to replicate those to another system.

[nsitps1976]

Ok, this is good news.

Are there any limitations / things I should be aware of if this route was taken? Does it complicate the process in any way?

[erick_moore]

No not really.  All you need to do when building LUNs is create a qtree first, and then build your LUN in that qtree.