Backup, Archive and Restore - The keys to Disaster Recovery and Business Continuity

As we come to the close of 2009 and the larger close of a decade, I remind all of you out there to test your backups. With recent events like the loss of flight data at Shaw Air Force Base and subsequent realization that backups were not working, it is more important than ever to test the integrity of your backup, archive and restoration platforms. It is no secret that enterprises have slashed IT budgets over the last few years, and some of this pruning came at the expense of backup platforms and personnel. In many of these enterprises, no one has stepped up to verify that the critical data backups (if they are even backing this data up) are valid. I implore you to not be one of the negative statistics. Let's take a look at the holy trinity of Disaster Recovery and Business Continuity.


Once a company has identified the business value of systems and data, they typically assign a risk value to losing those. This typically sets the wheels in motion to get a backup system in place. Backup, the very first step in Disaster Recovery and Business Continuity planning, is the base upon which you will build your strategy. Without the backup, there is nothing to archive nor restore later. Backing up typically entails duplicating data onto a secondary medium which acts as a safeguard against primary storage failure. This can be something as simple as a disk to disk (D2D) replication to a second storage system, or as complex as an NDMP stream across a fabric infrastructure to tape libraries waiting to write the data to magnetic tape media.


If we then take those tapes, on which we backed up our data, and move them to a secure remote storage facility, we have now archived that data. The main difference between a backup and an archive (although some hybrid solutions out there blur the lines a little) is that backups can be on-line or live while archives are typically off-line and stored somewhere other than the physical facility that the primary data storage resides. A disk to disk solution can be an intermediary to a full fledged tape backup and archive solution with the ability to restore data locally in a very rapid fashion. With an archive, you typically have to request the appropriate data set (on tape media) from the off-site facility, load it into the local tape library and restore the data from the media. This is essential for comprehensive Disaster Recovery and Business Continuity plans. If your primary physical location becomes unusable due to natural or man made disaster, you can relocate to a new facility and restore all data from tape media. The down time may be longer versus a local backup solution, but the down time is not permanent. Failure to have an adequate off-site data archival solution can result in loss of all data and permanent down time.


The end result of data loss or catastrophic storage system failure is a restore from the appropriate media. This final step should always be prefaced with several tests to validate the integrity of the data residing on the local or archived backup. When there is a loss of data, a local backup can be tapped to restore the lost data, or a data restoration from archival media can be made. Either way, the lost data is replaced with the last known good copy, and business continues as usual. Every successful restoration hinges on the validity of the data that was backed up in the initial stage. If any part of the backup and archival process failed, there is a good chance that the media will not be valid for restore. This issue can be compounded when your backup, archival and restore system does not properly alert an administrator to an error in the process. This is why tests of the backup media are so critical.

There are a plethora of backup, archival and restoration solutions on the market, and they vary greatly in cost and complexity. Some include features that many enterprises will not need, and some are missing in areas where a more robust solution is often warranted. It is most imperative that you first plan your Disaster Recovery and Business Continuity scenarios, then select the best platform to fit those. While one enterprise can get away with simple storage to tape archival, more complex enterprises will want array level replication to a hot site with local D2D cached copies and a full fledged tape archival solution. Adequate cost analysis and risk assessment should point you in the right overall direction. Avoid leaning on a particular vendor and seek the professional assessment and recommendation of a DR or BC adviser.

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