Sender: [EMAIL PROTECTED] > RAID of any level is NOT to be considered a 'backup' method. > There are no assurances built into raid for data reliability. > (ie. A program which writes corrupted data, a user who types > = > Identical problem with TAPE!! In fact it's even worse... Whats wrong with tapes??? With RAID you have just one generation, and the `save` is inside the machine all the time (fire, earthquacke), or do you exchange the disks for every save? This would be very expensive, compared to the price of tapes! I conclude that most replies are coming from people who didn't read the post. It's a NETWORK. I also conclude that most replys are about subjects/concepts I didn't raise or posters failed to read the price/performance data. Tape is generally a linear process with little chance of ensuring that the data was actually written correctly, a disk can be easily setup to verify the write. Tape is generally a "big block", an error wipes out significant data, in some classes all of it (hint: are you using compression to achieve the required capacity?). Disks are clearly different for typical errors. Tape lifetime is rather short compared to disk drives. Tapes are not expandable, entire tape systems need to be junked/replaced when network capacity does it's typical rapid growth, disks are easily expanded. The real question is "What is tape really good for?", but you need to be using tape for awhile to learn it's limitations. Alot of people think that an incremental backup solves the problem, until they need to do a restore... Consider the time cost (or it's savings) for random versus sequential access during recovery. The cost of a tape system, when the usual 10 to 20 tapes is included usually exceeds discount disk drive pricing for storage over 10 Gig when all costs are properly accounted. Look up the prices on the net, samples were posted. I have no idea where the concept of switching drives everyday appeared, it seems to have been invented for the purpose of knocking it down (as were most of the suggested strawmen). Posters generally are comparing 100Gig systems against the post, which covered SOHOs with 10 Gig networks. Wake up, there is clearly a economic difference between the two. The post was about software, I'm sure the mailing list is not interested in the other discussions. I've used tape, generally in avionics applications for over 13 years, know it's weaknesses and strengths rather well. I can count on one hand the number of times a drive has let me down, I need my toes for tape. Last off-topic comment: > Expand your thinking! I suggest you the same! Disks are much more expensive than tapes! How much costs you 100GB with disks? (n disks + n hotswap drawers) How much with tapes? (1 tapedrive + m tapes) 100 Gig of drives from Onsale: $3600. Could be lowered with a bit of patience. Hotswap not necessary, not main storage. However, a third drive is required, which makes it $5400. HP C5698 35Gig uncompressed, $6340 Tapes are probably $100+ each. QED.
