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There has been a lot of buzz in the air about CDP or Continuous Data Protection and what it brings to the table. So I thought it would be beneficial to spell out the capabilities of this technology and expand on how the title of this post (thanks BS for your Enlightenment) is spot on for describing the functionality of these appliances, specifically in the way of data rewind or PIT rollback.

To begin, what exactly is CDP?

In short, it is continuous backup. The ability to split every write ingress to a protected volume (LUN),  instantaneously. This process is performed  out-of-band or out of the data path, to an appliance (in this case a RecoverPoint Appliance). One item to note here, the concept of out-of-band is so important as introducing any devices in the data path has the tendency to impede I/O. Impeding I/O affects application performance, poor application performance leads to loss of productivity, etc,etc.. see where I am going with this….

Let’s continue…this “write splitter” can reside on the host (Windows Only) , on the array (CX and CX3 series arrays only (iSCSI and FC)-Support for AIX, HP-UX, Linux, Solaris, VMware and Windows) or within the Fabric (ie. Cisco’s SANTAP, Brocade’s Fabric Application Platform, RP version only). So a couple of things here, there is actually two versions of RP..as noted below..both offer local and remote replication but RP seems to provide the added benefit of fabric based write splits and multi-array functionality as well as the following: BW reduction, Heterogeneous Multi-pathing support, and up to 8 appliances per site, to name a few.

RecoverPoint- Geared toward multi-storage vendor environments. Comes with the CDP module for local synchronous replication intra-array or another same site array and the CRR module or Continuous  Remote Replication for remote asynchronous replication between multiple arrays. Both allow for data rewind (think TiVo) for point in time recovery.

RecoverPoint/SE (Single Edition? Array to Array implication)- Geared specifically toward CX and CX3 series arrays only, noted above. CDP and CRR modules exist as well  but purely for Clariion to Clariion replication with the added limitation of an 8TB cap. In addition, there is support for block based storage on the NS20, 40 and 80 FC models, but no support for the fabric write splitter among other things.

We all know a picture is worth a thousand words, so lets look at a typical RecoverPoint (forget RP/SE for now) environment and an explanation of each component (images by way of EMC)…

  The RP Splitter Drivers

• Out of Band write mirroring to the RP appliance
• Function can exist on the Host, on the Array, or within the Fabric

The RP Appliance-Thanks Kashya

• Runs intelligent RP software
• Handles Bi-directional replication
• Adherence to write order, Consistency Groups
• Maintains complete management and monitoring capabilities

The Importance of the Journal

• Delta tracker for all protected volumes-Stored in a compressed format for Point-In-Time rollback or rewind (did I mention TiVo)
• Bookmark Tracker for application aware recovery
• Maintains reserved pool to track changes to PIT (Point in Time) copies that have been recovered (target side processing space)
• SAN based LUN, easily expandable via concatenation or striped LUN expansions

Advance Networking Capabilities

• Pre-Flight data compression
• Eliminates the need for pricey FC/IP converters

The “Spread the Love” Support Banner

• Heterogeneous third party storage support, but please check the EMC Support Matrix
• Storage agnostic, any to any replication

Here is another great image depicting RP/SE, Clariion to Clariion Remote Replication…

What about licensing you ask?  Important question, so here is the answer…be sure to talk to you local EMC rep about specifics

• RecoverPoint is licensed by a per replicated capacity
• RecoverPoint/SE is licensed per array and ultimately that depends on what model of Clariion

Beyond this basic run through, which I hope was helpful, there are numerous integration points with this product to talk about. But there is one that I personally am very excited about, VMware Site Recovery Manager. So hold on to you hats as the next post should be a dooozy…;)