Luke S Crawford wrote: > Doug Hughes <[email protected]> writes: > >>> Are there any tape systems that have a lower cost per gigabyte than >>> 1TB or 1.5TB sata disks? >>> >> You don't offer much context to your question, but the answer is most >> assuredly yes. It depends how you want to use your tapes. >> >> 1 1TB enterprise seagate SATA disk is $200-$245 online (actually about >> 900GiB because they use power10 TB instead of power2) >> 1 LTO4 (800GiB) tape is about $48 in quantity one (significantly less >> in bulk) >> > > Interesting. hm. and the drives look to be around $3000 before the robot. > I do have a metric ton of 1gb fibre channel stuff laying about. > > But my experience with tape has been that it is way less reliable than even > the crappiest consumer-grade drives you can find. This may be ignorance or > incompetence on my part (I don't think I've touched a tape since I reached > the age of majority) - but either way, for me, tape has been unreliable, > and disk, while not completely reliable, fails in ways I've seen thousands of > times before, ways that I can deal with. (more importantly, when data is > corrupted on my spinning disk, my pager goes off. With tape, you don't > know until bob in accounting wants that really important file, > or the new guy wipes out the billing server.) > > See Andrew Hume's earlier message in the thread to refute the tape reliability for some class of tapes. (e.g. LTO, T-10000). It may be that you were just using crappy tapes?
... >> depending upon how many you buy and what your requirements are, tape >> is still significantly cheaper than disk, especially once you add in >> power for <x> TB of running disk. Tape wins in offsite archival as >> well. >> > > yes, power is a big deal. you have a good point there. > > I would argue that spinning disk is also pretty convenient for off-site, > though. spinning up a 16-bay supermicro under my bed (or in a co-lo on the > other side of the globe) is pretty cheap, and I can automate the 'tape > change' process as well as the 'restore file x from last week 'cause joe in > accounting screwed it up' process, and I can easily have multiple levels of > isolation. I guess you can probably do all the same things with a tape robot > of sufficient capacity/scriptability, but writing a interface to the spinning > disk system is trivial. > > For small scales of archival, that may be ok, but when you have TB of data that you want to keep for years, you have to look at things like the possible damage that will happen to a disk drive in transit, the relative size/density (starting to become moot), weight for shipping/transport for offsite archival, etc. > Another advantage of disk is that I already know about disk (and if the > new guy doesn't, she is going to learn fast or she won't be the new guy for > very long.) so usually, a relatively inexperienced SysAdmin can come up > with a reasonable backup solution using spinning disk. Something that > lets joe in accounting retrieve the really important file he screwed up > yesterday. Using tape, well, doing anything besides a full restore requires > some specialized software, and at nearly all of the places I've worked, is > simply not done. > You seem to be talking about tape for backup, for the most part. There are big wins to be had using disk backups, there's no doubt about that. Tape still seems, imho, to be the best choice for long-term offsite archival of data that will be kept for "a long time"*. It's cheaper, generally has a lower undetectable error recovery rate, lighter (cheaper to store and transport), and has better robustness for transporting. * - for certain values of "a long time" _______________________________________________ Tech mailing list [email protected] http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
