Are backup tapes headed for the graveyard?

I read an article today in Byte&Switch ( Link ) called “Can’t quite kick the tape habit” ( Read-it-here ).  This article seems to imply that actual tape backups may be going by the wayside in favor of Disk storage unites and VTL (Virtual-Tape-Library) systems.

I think the author is on crack, and that while the disk vendors would very much like to see tape go by the wayside, it’s simply not going to happen. 

Add that to the fact that most companies, including mine, will always require the ability to archive off tape.  (This presents a challenge when it comes to people who use backup products like Veritas (www.veritas.com) because are we really sure that the tape format (Veritas writes all it’s tapes in GnuTAR format) is going to be readable after so many years?

A virtual tape library system, at least the ones I’ve read up on in my research, are basically disk arrays filled with inexpensive and not-so-fast disks, that in turn are carved up and utilized exactly as a tape library, with volume numbers, a “robot arm” and such.  (Network Appliance (www.netapp.com) and FalconStor (www.falconstor.com) both make VTL units)

I’m sorry, but there isn’t a virtual tape library in the world that will handle very-long-term retention.  Especially in the volume that we do.  Our disk storage unit is 17TB of 500G SATA drives.  At any given time, with only two weeks of backup data (Fulls on weekends and differentials daily) that storage unit runs at about 70% capacity.  And this is with just six months of data.  I can’t conceive of how much storage would be required to maintain 30 years of data.  (actually, I can, without growth it’s 6.35 PETABYTES in 27 years)  I had planned for about a terabyte a year in growth at minimum, (and some say my estimates are very low) and if my math is right, (234*27+(52*(27^2)) that’s about 44 petabytes of data after the 27 year mark.  Mind you that’s the point where we can start expiring our first tapes.

As much as EMC would love us for it, I don’t think we’ll be buying that much Clariion space in the near future. 🙂

The down-side to tape is obvious.  No tape manufacturer will guarantee their tapes in storage for more than 7 years.  So now what we have to do to ensure restorability, is after five years, every month we will bring a set of tapes back and duplicate them to whatever the “format-du-jour” is and send the new tapes back out. 

Then again, I know companies who put all their faith in CD-R storage, before all the stories of “Laser-Rot” starting coming out.  (The fact that if you didn’t use a CD Friendly marker on the CDR, that the ink would seep in and oxidize the surface of the disk making it unreadable – Sharpie(tm) brand markers are not by default CDR friendly, though they do now make one that is.

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