Whitepaper: EMC SAN Copy

Source: eGroup EMC Data Migration to VNX

EMC Data Migration to VNX –

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EMC Data Migration to VNX

As a result of the huge success of EMC’s VNX platform, the need for data migrations has grown, especially recently, to get customer’s data safely and easily moved over from their previous storage platform to their shiny new VNX.  Here are some ideas on migration strategies that hopefully help you in the planning or execution of data migrations! Keep in mind that almost every one of our customers are heavily virtualized, the vast majority of which run VMware vSphere– so it is in that context that the following “strategies” are presented.

The “strategies” listed below are NOT exclusive of one another– in fact, we commonly use a combination of all 3 to provide a “total solution”. And there are some other strategies and techniques used to aid in the migration of data that aren’t covered that work just fine.

“Strategy” 1

First and foremost, the BEST and EASIEST data migration of all can be done without any downtime, and with zero risk. This is accomplished by using Storage vMotion (svMotion), and means you are migrating over some of your virtual environment to the VNX. It requires that your data exists in a VMDK (meaning it’s a virtual machine and that drive is NOT an RDM), and that you’ve created and presented storage from the VNX to the vSphere environment. This method works like a charm!

“Strategy” 2

For environments that have a lot of physical servers (which hurts my feelings by the way– virtualize ‘em already!), or use lots of RDMs, there are some alternative options, most common of which uses EMC’s SAN Copy software. SAN Copy is included on the VNX platform for FREE, and for customers migrating from an EMC CLARiiON, EMC will provide this to you at no charge (again, read FREE) for your CLARiiON, (to be used for migrating to the VNX).

SAN Copy is installed as a “software enabler” on the desired arrays and allows the copying of data between arrays, in either a “push” or “pull” method. The method, push or pull, is determined by the array initiating the copy job (if it’s the “old” array, it’s a push–).

This can also take place between an EMC array and a “qualified non-EMC storage array”, but only in a “pull” fashion.

Using a “push” method (where you’re configuring and starting the SAN Copy job from the array you’re migrating FROM)  allows you to do Incremental SAN Copy jobs. This let’s you do a single full copy, and from then on only copy over the changed/delta data.

It’s important to note that this is “host independent”– meaning the host servers are not involved. This DOES require downtime to cutover, unlike strategy 1 described above.

Note: This doesn’t get configured the same way it did on the CLARiiON platform when going “CX to CX”. I’ll work on getting a video together showing the difference, but for now just know that when you create the SAN Copy session, the “remote LUN” isn’t something you select (today)– you must enter the unique ID of the LUN instead (see screenshot). Kind of a pain, but not unbearable.

“Strategy” 3

When migrating over your file server(s) or file server(s) data, consider skipping the “copy to a LUN” or svMotion methods, and move straight to using the CIFS server capabilities of the VNX. This is a larger conversation, but in brief, the VNX can operate as a Windows file server, where you give it some disk space to use, a name and IP address, and join it to the domain. It will appear as a regular computer in Active Directory (you can create multiples if you’d like as well– for security or isolation between departments, companies, domains etc.), and you can even include it in your DFS environment.

The BENEFITS of this are numerous, and include:

  • FILE DE-DUPLICATION! This is one of the BEST reasons to move your file server data to the VNX. Huge storage savings, which ultimately means “YOU SAVE MONEY”! (see screenshot below– 43% of all files were deduplicated!)
  • Highly available, highly resilient file server. Since the platform itself maintains 5 9’s of availability, your file server doesn’t have a single point of failure, which it would if it was a stand-alone Windows server (think about what happens if the OS blue screens for example).
  • High performance hardware designed to serve files!
  • Thin Provisioning– only commit what’s actually being used, again, saving space/money.

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