BEDTIME READING-Tapes, Just say NO!

From: Jay Nugent <jjn@home.nuge.com>


When I was looking to get myself a home computer back in the 70's a friend gave me these words of wisdom: "Don't bother with punched paper tape, it's slow, it's undependable, it's old, it's outdated. Get a disk".

I heeded his words and avoided buying any of the tons of paper tape equipment that was then showing up at Hamfests and Swap-n-Shops. I can say I never regretted following his wisdom.

When I was looking to get my first PC-AT a friend was trying to convince me that I needed a tape backup system to back up my incredibly large (at that time) 1.2 Gig hard drive. I just couldn't convince myself that magnetic tape was anything more than punched paper tape, just in a slightly different form. Especially after watching him struggle with tape restores that never seemed to work. Needless to say, I have NEVER bought a tape backup system.

Over the years I have always backed up my data by tarballing the needed directories and config files then FTP them off to another machines hard disk. Okay, not the elegant GUI solution many folks would desire. But I could guarantee that nomatter what flavor of Linux, what revision of the libs I have, what type of windows manager, I could always *manage* my backup data.

This summer a client of mine in Lansing Michigan called me. He had just spent $400-500 of the companies money on a new tape backup system and ten or a dozen blank tapes. He had just spent the last 3 DAYS getting it all installed, configured, and SORTA working. Problem was, every time he went to restore from tape (which took quite awhile to do) everything but the last few files would restore, but NOT the last couple files. This had him baffled and frustrated...

I posed this scenario for him. Let's say he gets this tape system working perfectly. Perfect daily backups (incremental), perfect weekly backups, even perfect monthly backups (full). Let's say he even has the forsight to move his backup tape OFF-SITE (as every good backup procedure should do). Then Godzilla comes to town. Pissed-off at all the little people shooting projectiles at him, he decides to stomp on your business. Crushing the machine(s) that your business relies upon, into tiny pieces. Oh! Not to worry. We have *BACKUPS* :-)

Okay, Godzilla is forced back into the sea in short order. Now your fun begins. You need to get your ENTIRE COMPANY back online as quickly as possible. You begin by buying a new PC from the local computer store. You have your backup tapes in hand, but OH! Now I need to find a tape drive that supports my tape format. Okay, maybe with luck it's not more than a *couple* years old and there's one available at the computer store. Likely you'll have to order one or beg, borrow, steal...

So far, so good. Now you begin re-installing and configuring the tape system. Remember it took this guy THREE DAYS to get it working, and that wasn't with the ENTIRE COMPANY BREATHING DOWN HIS NECK :-( So, you work well under *extreame* pressure and you get it installed, configured, and working. You perform your restore and all is well. Happy ending, we hope... But is this *really* the way you think it should be?

NOTE: Godzilla can be replaced in the above scenario with a tornado, fire, flood, burgrary, bomb, building colapse, arson, or just a simple power failure (and no way to run a generator 'cause you're on the 15th floor of a 30 story building).

Let me suggest another scenario. Instead of a tape backup system, you opt to buy another hard disk (same or larger size than the one being backed up). With the money you would have spent on the tape-drive, boxes of tapes, and cleaner, you also buy a box with roughly the same hardware as your production box (same ethernet cards, same vide cards, etc.). You place the 'backup.mycompany.com' box on the Internet at a location across town or in another town (hopefully somewhere where Godzilla won't likely stomp on both your business AND your backup site). "Diversity is Good (tm)".

In this 'backup' box you have two hard drives. The first drive is for booting and contains a very simple install of your favorite Linux. No services on this box 'cause you want it to be as secure as possible. The second hard disk is the one that will contain your backup.

The first time you bring up this system you use rsync or mirror to build an exact image of your production system. From then on you use a cron job to launch 'rsync' every night to automatically update EVERY file that has been changed. Rsync is VERY efficient in that it ONLY copies over that data that has changed, NOT the ENTIRE file. So if you added a few lines to a large log file, only those changes are transfered over the network. We now have an almost exact copy of the production disk (minus whatever has changed since our last backup, but that 'data risk period' exists for magnetic tape backups as well).

Back to our disaster scenario. Godzilla comes out of hiding and begins stomping your business into the sand. Not to worry, we have "An Even Better Backup (tm)". We simply readdress our second hard drive to be the first (bootable drive). Apply power and YIPPIE!!! The backup box has now become our new production box. Same IP address, same type ethernet card (no reconfig neccessary), same video card (no reconfig neccessary), and most importantly...the same DATA that was on the old now pulverized disk.

We place this puppy back on our company Internet connection (as soon as it gets restored) and the company is back in business. The employees chear "Oh boy, we get to go back to the Salt Mines"! The boss offers you a promotion, a big raise, his beautifull daughters hand in marriage, stock ownership in the company, and a big pat on the back :-)

Tape: Just say NO!
 

searchSearch Index