Survival Guide for Tape Backup and File Storage

Welcome to the best tape drive survival guide.....EVER!
I'm sure most of you are thinking "Tape backup? Who uses tapes anymore?." The answer is most businesses, large and small have a need for a backup solution that can handle a large amount of data, can be transported off-site, and is relatively inexpensive. For reasons unknown even to me tape drive units continue to advance in performance and overall storage capability just as the rest of the many pieces of hardware that complete the IT world.

Tape Storage Benefits:

The benefits of tape storage are of course the only reason tapes have survived thus far. Tapes can hold a great amount of data for their size and are not expensive to replace if dropped, lost, stolen, melted, or simply destroyed. Backup speeds will depend on your drive and are not usually impressive which is why most backups are scheduled to run in the late night/early morning hours. Tape drives are for the most part reliable when maintained correctly and installed in a friendly environment (away from magnetic fields, dust, and heat.) Finally tape backup units are fairly simple to operate and with the right software may never need your attention at all. Users can simply insert the tape labeled "Monday" before leaving for the night and swap with the next day's tape upon arriving back to work.

Downfalls:

I'll be honest - tape backup is risky. Statistically tape backups are successfully backed up and restored/verified about 50% of the time. Why so high of a failure rate? I will be honest again, the user. Most of us tend to fire and forget when it comes to running backups, especially when automated. The problem is tape drives are picky! They want cleaned (depending on the model) about every 3-4 backups or every 8-10 hours of operation time. Most drives come with a standard cleaning tape which usually needs replaced itself about once every 6 months - 1 year, again depending on your backup situation. I cannot stress cleaning enough, although some drives, namely LTO (linear tape open drives), can be over-cleaned so check your manual or vendor for the right cleaning schedule. Tape backup units are also notoriously slow and generally complete large backups in a matter of hours. The negative factors may be ugly but I'm sure you will find that the pure ability to backup loads of data consistently will outshine.

Preventive Maintenance!!!!!

Clean, clean, clean. I cannot stress it enough. A tape drive has a magnetic head just like any other tape device and it gets DIRTY. New tapes can actually make the head dirtier than your tape from last year's exchange backup. All environments have some form of dust. Microscopic or chokingly visible, dust is your enemy. The next HUGE factor in maintaining a TBU (tape backup unit) is firmware. I hear it all the time "My firmware is recent/ up-to-date" which is probably true but firmware for some reason is easily corrupted in TBU's. Don't ask me why, but I can speak for thousands of clients who have had problems with write errors, stuck tapes, and even weird grinding noises. Firmware will solve about 85% of all backup issues if things were picture perfect or slowly went downhill before you began having trouble. If you have the most recent firmware that's great but I would recommend re-flashing it again every 6 months. Firmware can be found on the computer or TBU manufacturer's website and will usually come with diagnostics for further investigation if you are troubleshooting the drive. Lastly be sure to rotate media as you cycle through your backups. Running a daily backup on the same tape over and over may yield some disappointing results. Your backups may be finishing without error but when it comes time to restore from the overused tape it may be that one time that it decides to fail you. I would recommend checking your TBU's manual for "mean-time-before-failure" stats on media so that you can replace and retire old media before corruption occurs. Most backup software will keep record of hours each tape has been used and even notify you when it's time to clean. Waiting for the drive or software to ask you to clean is a bit much to me, almost like waiting for your vehicle to tell you it's time to check the oil. Not good!

Tips, Tricks, and FAQ's.

The biggest misunderstanding I hear from my clients is the tape drive capacity. A 40/80 GB tape drive will backup 40 gigs native and 80 gigs compressed. A manufacturer bases these figures on theory, just like hard drives. So when theory is applied to reality confusion ensues. The drive can natively, or by default backup about 40 gigs of raw data without compression, which if no compression is used you might get about 35-38 gigs worth before reaching the end of the tape. You will never get the full compressed 80 gigs out of the drive, it's just not possible. The amount of compression is also another big concern. You may be using full hardware or software compression when running a backup but the compression ratio is going to depend on the files being backed up. If you are backing up jpeg, mp3, zip, or simply a file format that is already compressed you will see little to no compression. It's like trying to zip a zip file. The file types that see the best compression ratio are generally text based files such as sql databases(almost any database), documents, etc.

Backup software also has a lot to do with TBU behavior. One example is if you are using Symantec's Backup Exec you do not use the manufacturer's driver for the drive. Backup Exec runs its own driver and if not used can cause major backup failures before even writing a single block to the tape. Some backup applications require that you completely disable your tape drive in the OS completely. If you are having problems with your tape drive in a backup application the next best thing is to try and duplicate the problem in the NT Backup utility included in all current Windows releases. Found from Start> Programs> Accessories> System Tools> Backup. This is the standard backup utility that is installed with windows and is actually pretty user friendly but lacks some of the advanced options of 3rd party software.

My tape is stuck! This is one of the most common problems with tape drives. It could be mechanical or a simple timeout to the SCSI controller operating the unit. If this happens hold the eject button located on the front of the unit for 30 seconds to a minute. This will usually cause the tape do cycle and eject. If it doesn't work the first time try it while the system is rebooting. If holding eject does not work try flashing the firmware. Flashing the firmware to the same or upgraded version issues a eject command to the unit before writing the new image to the drives internal flash memory and in most cases will get a stuck tape to eject. If firmware fails then it's time to run diagnostics as this is probably now a hardware problem.

Diagnostic utilities for tape drives are very stripped and standard. They tend to have options for a read and write test, SCSI communication test, tape operation tests, or LED (lights on the front of the drive) test. If you are having problems with writing, reading, or even loading media, diagnostics usually narrow down the issue to hardware or firmware/software.

Aside from utilities and updates the actual inspection of the hardware may solve most tape drive problems as well. Most important is termination. Most tape drives require that they are terminated. The terminator will either be located on the back of the drive if it is external or at the end of the SCSI ribbon cable if it is internal. Terminators will almost always have a green led indicating proper termination. If it is out thats probably your problem. SCSI cables are also fragile and can cause communication or detection problems when pinched, twisted, or too long. If you are having problems even getting the drive detected check the cable connections on the drive side and the controller side. If you cannot see the tape drive in your OS then see if that is the case in the controller BIOS which can be accessed while your system is booting and following the prompts. SCSI ID configuration can also cause communication or detection problems. A SCSI controller always assumes, by default, the SCSI ID of 7. your tape drive will come set to a default of 6. If you have any other devices on your SCSI controller check to be sure they do not share the same SCSI ID. Another common problem is plugging tape drives into RAID controllers. It's possible on some newer RAID controllers but I don't recommend it. You will either end up with RAID corruption or complete failure of your RAID array or tape drive.

There are many other small factors to configuring and maintaining a drive which can be researched through the manual or vendor of the drive itself. Backing up and restoring with success is always gratifying and so is knowing your chance of success is high. I hoped this article has helped answer some questions or even solved problems for some of you out there! Be safe and remember the cleaning!