Just a couple of questions and an observation or two. I've seen the 100gigabyte disk drives, you speak of, advertised as a near-line backup solution. Sounds good up front.
Tape drives at 4 times the 100GB low-end drives? I wish. A good enterprise quality tape drive costs from $8,000 to $35,000USD. Three year tape life? A little low on that estimate. The newer tapes (DLT8000, LTO, MagStar) have rated shelf lives to 30 years. The cost of these tapes range from $40 to $110USD with native capacity ranging from 40GB to 110GB. CD-R? Have you tried to backup 500GB+ to CD-R? I hope you have an automated jukebox with about a hundred CD capacity. How about 10TB+? Have you calculated the cost for maintaining a reasonable backup rotation? That would be one to two years. Even at 30 cents per CD-R (650-700MB), the costs would become staggering. Now calculate it for hard drives at 20 cents per gigabyte. How do you accomplish off-site storage for disaster recovery(DR) with backups on hard drives? If you read the advertisements for the backup to hard drive solutions, they mention that you still need a tape solution for disaster recovery. If you don't have the need for off-site storage and can recover from a catastrophic hardware failure without it, then it might make sense for your situation. Of course, your backup rotation is limited by disk space. Just to give you an idea, on one system, our backup rotation looks like this: Daily backups: 5 days (5 - 8 tapes) retained for 5 weeks Weekly backups: Forced full and vaulted (8 - 10 tapes) retained for 13 weeks Monthly backups: Forced full and vaulted (8 - 10 tapes) retained 12 months (vaulted - copied to a second tape to take off-site for DR purposes) Total number of tapes in use is ~300. That's 12TB native, but with compression rates running about 2:1 that's 24TB of storage. That would be about 240 100GB disk drives to provide that capacity. Now you're at $48,000 -- not counting the racks and arrays in which to mount the disk nor the scsi, ide or fibre channel connections to talk to it. Don't forget power consumption; floor space for racks; etc. At $48,000, you've spent more than we have for our solution, including tapes and maintenance. If you're doing this at home, then yeah that probably works. That's how I backup my systems. Wayne Richards > Michael C. Robinson > > 100 gigabyte hard disk is less than $200 while the last check on high capacity tape >drives turned up prices exceeding 4 times that for maybe a quarter the capacity >because advertised tape capacity is compressed capacity. Worse, tapes don't last, > they have a three year shelf life if they are stored properly and the tape doesn't >physically break when it winds around the spools... > > Is it possible to configure Amanda to backup to a harddisk or Raid volume instead of >a tape? What about CD-R, it's the cheapest media and it has a thirty year shelf life >where the only downsides are the capacity, the risk of disks getting scratched, > the fact that they are made using mercury, and the risk of them getting exposed to >UV light. > > I'm asking about the issue because the recommended book to read on Amanda suggests >that Amanda > doesn't offer an alternative to tape backup. My last search on tape drives >suggested that a high capacity unit that can handle 40 gigs per tape is between $800 >and $1000. I could buy a lot of ATA hard drives for that kinda cash.
