backup solution 4577

John-Paul Stewart

I, too, run BRU, but my LAN once had three machines on it, which is pretty small by most standards. I have an Exabyte VXA-2 on my main machine and a VXA-2 on the other. The third machine has been given to the deserving poor. While it is theoretically possible to back up all three machines from the one with my highest capacity hard drive, I do not choose to do that.

My VXA-2 can get 40GBytes (buttuming 2:1 hardware compression) on one of their smallest (V6) tapes and 160 GBytes (2:1 compression buttumed again) on their V23 or X23 tapes. A V6 tape costs around $27 in lots of 1, and an X23 costs around $73 in lots of 1. The X6 tapes (same capacity as V6, but will not run on a VXA-1 drive) are only about $16 in lots of 1. If you cannot get everything onto a single tape, Exabyte make various models of automatic tape changers. VXA drives cost around $1000, but they are available at a discount on the Internet.

The VXA-3, projected to be released late 2005 will be twice as fast and double the capacity. The VXA-4, projected to be released sometime in 2007. is planned to have double the speed and double the capacity of the VXA-3. The intent is that they are all upward compatable in the sense that a faster drive can read tapes produced on the slower ones. I know for sure that tapes written on one machine with a VXA-1 drive can be read with no trouble on the VXA-2 on the other machine. The VXA-1 is about 4 years old and the VXA-2 is a bit over a year old now. The only maintenance I have done is to run a cleaning cartridge through the drives when the amber led flashes.

My latest backup (early this morning when I was asleep, had the following results:

Started: Sat Aug 27 01:08:04 2005 Completed: Sat Aug 27 02:07:21 2005 Archive id: 430ff534281d Messages: 0 warnings, 0 errors Archive I-O: 6502848 blocks (1300568 plus 16Kb) written Archive I-O: 6502848 blocks (1300568 plus 16Kb) read Files written: 247635 files (206770 regular, 40865 other) Files read: 0 files (0 regular, 0 other) Files skipped: 0 files Write errors: 0 soft, 0 hard Read errors: 0 soft, 0 hard Checksum errors: 0

I.e., in slightly under an hour, it backed up a bit over 13GBytes of data, and then read it all back and checked it. Call it 13 GBytes-hour written and checked. AFAIK, an LTO-2 is about 8.3x faster than this and one model drive can take 400GBytes compressed.

Of course, by Murphy's Law, a power surge, lighting strike, home fire, or OS going mad, will do just that. Are hot swappable hard drives now cheaper than tape cartridges?

That is for sure. That is why I have 23 tapes for each machine.

Monday, Tuesday, ..., Saturday First Sunday, Second Sunday, ..., Fifth Sunday January, ..., December

This way, if I stupidly mess up or delete a file, and discover it immediately, I can recover a copy under 24 hours old. If I do not notice for about a week, I can get one under a week old, and if I do not notice for almost a month, I can get one under a month old, and if almost a year goes by, I can get one under a year old. After that, I am out of luck, but I could keep annual tapes if there were a need for it (like running a business).

I keep all but the current tape in a different room from the computers, and the monthly tapes in the safe deposit box at the bank. I sure would not want want to buy 46 hot swappable hard drives or store 24 of them at my bank.

-- .~. Jean-David Beyer Registered Linux User 85642. V PGP-Key: 9A2FC99A Registered Machine 241939. ^^-^^ 13:25:00 up 73 days, 7:20, 3 users, load average: 4.22, 4.14, 4.14