Thanks to Hu Yoshida for the reference to a previous post of mine which mentioned using virtualisation (USP, SVC, take your pick) for performing data migrations. As Hu rightly points out, the USP, USP-V, NSC55 and USP-VM can all be used to virtualise other arrays and migrate data into the USP as part of a new deployment. However nothing is ever as straightforward as it seems. This post will discuss the considerations in using a USP to virtualise and migrate data into a USP array from external sources.
In summary, here are the points that must be considered when using USP virtualisation for migration:
- Configuring the external array to the USP requires licensing Universal Volume Manager.
- UVM is not free!
- Storage ports on the USP have to be reserved for connecting to the external storage.
- LUN sizes from the source array have to be retained.
- LUN sizes aren't guaranteed to be exactly the same as the source array.
- Once "externalised" LUNs are replicated into the USP using ShadowImage/TSM/VM.
- A host outage may be required to re-zone and present the new LUNs to the host.
- If the source array is replicated, this adds additional complication.