You've always been very careful to keep your backups up to date. You've been swapping out your tape media on schedule. Everything was going right, until…

Your hard drive failed. You've tried everything you can to recover it. You've sent the damaged drive off and they called you and told you the data was unrecoverable. You installed a replacement drive, and you've followed the instructions to reinstall the operating system. You installed all of the proper device drivers, you tape drive came online fine, and you threw in the first tape in your archive. Everything goes fine with the restore till you hit the last tape in the series, and find it's unreadable.

Basically, tape data recovery is getting lost data back from tape cartridge that has been damaged in any number of ways. The damage could have been the result of heat, smoke, or water. The tape might have been overwritten, been placed out of sequence, or the tape drive write head was faulty. Data recovery from a tape is similar to any other form of media recovery; it can be broken down into two methods.

• Physical recovery involves dealing with damage to the media. Bad or broken tape or anything that prevents the drive from reading the tape. This can also involve recovery from environmental exposure such as flooding or damage from a hurricane. The tape can be repaired, cleaned, or re-spooled onto a new cartridge. Then the data can be recovered using special hardware.
• Logical recovery involves fixing corrupt data on a tape that was successfully recorded, but can't be read for non-obvious reasons. Data recovery from this type of problem usually involves special tape drive hardware that uses multiple passes using software that restores the file to a hard drive. In case errors still occur, dummy blocks are written to replace the bad blocks, and then the fragments of the file are reassembled and rewritten. Some tape errors occur because the drive that originally wrote the tape's write head was misaligned. Again special hardware can be used to recover the track, and rewrite it to replacement media. The faulty tape drive can then be recalibrated or replaced.

Either form of recovery should be performed by a professional data recovery service. Many companies of this type actually specialize in tape recovery, and provide a quality service for your money. As always, be very careful selecting your data recovery provider. Request a quote upfront, and make sure that you talk to a representative on the phone. Understand what you're getting up front. This is no time for any unforeseen surprises. Most companies also offer a guarantee on their services, and will give you a time frame when you get the quote.

Tape failure is very uncommon, but it does happen. It always pays to be prepared to minimize the downtime that a disaster causes.