What you will learn in this tip: Organizations that rely on removable media for data backup and recovery often ship the media off-site in case of a disaster. But what if you have a problem and need to restore
the media right away? Learn how to prevent removable media storage recovery disasters with redundant backups in this tip.
Early in my IT career, I learned a difficult lesson. The company I was working at required me to make a full backup of each server every night of the week. Each morning my backups would complete at around 7:00. At 7:30, a courier would arrive to take the previous night's backups to a secure facility. The courier was aware of our tape rotation scheme, and would provide me with the tapes that were to be overwritten by that night's backup.
Keeping copies of the organization's data off-site would ensure recoverability if the building were ever destroyed (which nearly happened on two separate occasions). One day, however, we had a disk controller failure on one of our file servers. The failure caused our entire RAID array to become corrupted. I was able to repair the server and rebuild the array fairly quickly, however, I had no way of restoring the data. All of my backup tapes were stored off-site, and I had no way of retrieving the tapes that I needed until the next morning.
Even though this incident happened many years ago, the circumstances are still relevant today because organizations that rely on removable media backups are forced to choose between leaving the media on-site where it can be easily restored, or shipping the removable media storage off-site where it can be protected against fires and other unforeseen catastrophes.
Thankfully, technology has improved over time, and there are now several options for dealing with this dilemma that simply did not exist many years ago.
Solutions for removable media storage recovery problems
One option is to use a disk-to-disk-to-tape (D2D2T) backup solution with continuous data protection (CDP) to perform D2D2T backups. CDP tools perform incremental backups throughout the day. The data is written to a storage array on a dedicated backup server, and then the array's contents are backed up to tape. The advantage to this type of solution is the backup tape is only needed in the event that the backup server fails. Otherwise, you can restore data directly from the backup server, which means that you can store your backup tapes off-site without having to worry about their accessibility.
Another solution to the tape storage problem is to use media cloning. Many common backup applications such as CA Inc. ARCserve and EMC Corp. NetWorker offer support for media cloning. Media cloning is a technique in which two identical sets of tapes are created simultaneously by the nightly backup. That way, you can store one set of tapes onsite, and ship the other set offsite. Media cloning has the added advantage of protecting you against bad tapes by independently creating a duplicate of every tape.
But media cloning requires more than just software with a media cloning feature. You must also have compatible hardware. Thankfully, most tape libraries can be configured to create duplicate sets of tapes.
I'm a big believer in the idea of keeping an off-site copy of your data, but experience has shown that it's equally important to keep your backups accessible. Cloud-based storage aside, the ideal solution is to create redundant backups so that you can always have a local copy and an off-site copy of your backups.
About the author: Brien M. Posey, MCSE, has previously received Microsoft's MVP award for Exchange Server, Windows Server and Internet Information Server (IIS). Brien has served as CIO for a nationwide chain of hospitals and was once responsible for the Department of Information Management at Fort Knox. You can visit Brien's personal website at www.brienposey.com.
This was first published in November 2010