1TB RAID 5 Array

Alright, my new server will have a 1 TB RAID 5 array.  Every computer I have will push backups to it. By your logic, to make a full backup of that I would need 112 Dual Layer DVD-R’s per copy, so 336 total to have one set at my place in my fireproof safe, one at the family house in the fireproof safe and one set in use. Also, in the event of a fire the data would be destroyed inside the fireproof safe since temperatures inside it can rise above that tolderated by DVD-R’s. And we won’t mention that during the backups I need to manually swap each and every disc, or if I get a jukebox I’ll still have to swap an inordinate amount of time.

Now let’s compare that to DDS-4 or DDS-5 that I’ve chosen.

With DDS-5 I would need 14 tapes in a library, as each tape has a capacity of 72 GB, and with DDS-4 I would need 25 tapes with a capacity per tape of 40 GB. I would have them after a fire and they support many times the write speeds of DVD-R and include simultaneous writing to multiple tapes, plus they will automatically back up if I’m not there. If I want to, I can even use them as near-line storage for items I don’t use a whole lot: especially with the 8 GB DDS-2 tapes (which DDS-4 and DDS-3 drives are backwards compatible with) being able to convienently hold an entire movie and play with only a few seconds delay.


So you were asking if it wouldn’t be 1) cheaper, 2) faster and 3) more prudent to upgrade to network storage or DVD’s. 1) no, spending $300 on the library and $100 on tapes is definitely not more expensive than buying 336 dual layer DVD-R’s. 2) no, I can only write little over 500 MB/min with DVD-R and I have to manually swap discs, with DDS I get that speed PER DRIVE and can use multiple drives simultaneously (I’ll be using at least 2), plus they automatically swap tapes to speed that element up. 3) Is it more prudent to use a technology that will survive fire and doesn’t need to be replaced often (DDS tapes and drives can last decades) than use something where I’m burning the the entire lifetime of the DVD burner every couple of weeks and am replacing them once a month or so? How about when I have to toss the DVD-R’s: even with DVD-RW I need to replace them every 10-12 uses or so.

FYI: If I used LTO Ultrium (another tape technology) I would need only 2 tapes for my entire array. That’s for big enterprises though: It’s a $2000 drive.