Data Centers

Pros and cons of replication and tape for data protection

IT pro Rick Vanover considers the decision of data protection exclusively via replication or by relying on the venerable tape device for small and medium businesses.

Offloading to tape is a data protection strategy that does its purpose well, but can surely be made better in today's IT landscape. There are good things about tape, such as its ease of transport, low cost, and the relative safety of accidental deletion. On the other hand, the critiques of tape are in no shortage. Tape can have reliability errors that mysteriously only seem to happen on a restore as well as occasionally falling off of a truck. For the small and medium business, these are important factors as alternatives are limited.

Administrators today have a viable alternative in using replication technologies to another site to meet a fundamental requirement of storing backups off-site. This site can be another location within the organization accessible via a private network, WAN or Intranet. This site could also be a cloud storage provider for data protection, which I still think can be the first way organizations migrate to the external or public cloud. I want to keep cloud out of this discussion and focus on replication and tape for migrating protected data off-site.

Replication technologies can be done a number of ways. Take for example a common configuration that backs up systems and data to disk first and then offloads the retained data to tape. The system that performs the backup has an archive of the systems it is protecting; in many backup software products, this is the second tier of protection. The third tier would be the offload to tape. If the backup system and its associated second tier storage are replicated to another system at another location within your organization, are your off-site requirements met? These replication techniques can include any of the following:

  1. Protection tool software This replication can protect a physical or virtual machine via a software tool such as Acronis, Novell PlateSpin Protect, DoubleTake, Symantec Backup Exec System Recovery, Veeam, and others to a storage resource at another location on your network. These tools can continually create an image or update on a specified interval.
  2. Storage-based replication Many SAN products now include the ability to replicate LUNs from one storage controller to the other.
  3. Management software Scheduled tasks to clone a system (such as a virtual machine) to another location in your organization.

With these options, there is one crucial caveat. If a software or user error deletes data or other important content on the source, is it replicated to the protected site? Tape can have an advantage here by being removed from continuous I/O.

Replication technologies would propagate the deletion through all protection tiers if they are real time. The only way a protection policy can really be successful with replication is to have a schedule to accommodate for accidental deletion or additional tiers of protection that provide a point-in-time recovery within the tools in use.

I'm not exactly a fan of tape, yet there are many considerations to going to replication-only for off-site data protection. What are your thoughts on this transition and how your requirements apply?

About

Rick Vanover is a software strategy specialist for Veeam Software, based in Columbus, Ohio. Rick has years of IT experience and focuses on virtualization, Windows-based server administration, and system hardware.

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