On 19 jan 2010, at 20.11, Ian Collins wrote: > Julian Regel wrote: >> >> Based on what I've seen in other comments, you might be right. >> Unfortunately, I don't feel comfortable backing up ZFS filesystems because >> the tools aren't there to do it (built into the operating system or using >> Zmanda/Amanda). >> > Commercial backup solutions are available for ZFS. >> I know tape backup isn't sexy, but it's a reality for many of us and it's >> not going away anytime soon. >> > True, but I wonder how viable its future is. One of my clients requires 17 > LT04 types for a full backup, which cost more and takes up more space than > the equivalent in removable hard drives. > > In the past few years growth in hard drive capacities has outstripped tapes > to the extent that removable hard drives and ZFS snapshots have become a more > cost effective and convenient backup media.
LTO media is still cheaper than equivalent sized disks, maybe a factor 5 or so. LTO drivers cost a little, but so do disk shelves. So, now that there is no big price issue, there is choice instead. Use it! Hard drives are good for random access - both restore of individual files and partial rewrite. Hard drivers aren't faster than tape for data transfer, but they might be cheaper to run in parallel and therefore you could potentially gain speed. Hard drives have shorter seek time, which may be important. Hard drives are probably bad for storing for longer times - especially - you will never know how long it could be stored before it will fail. A month? Probably. A year? Maybe. Five years? Well... Ten years? Probably not. LTO tapes are supposed to be able to keep it's data for at least 30 years of stored properly. Hard drives are probably best when used online or at least very often. So - it is wrong to say that one is better or cheaper than the other. They have different properties, and could be used to solve different problems. /ragge s _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
