On Wed, 2008-09-17 at 16:42 +1200, Spiro Harvey wrote: > > If we add hard drive storage for backups instead of buying LTO-3 tape > > drive, how much storage would we want for backing up 2Tb of binary > > data...surely not 6 Terrabytes? > > > assuming that three week rotation is full backups only, then 2x3 is > indeed 6. > > However, most people do incremental backups daily and fulls once a > week. If this the case, you will need more. > > Your backups will probably be compressing the files, or rather, > archiving them into tarballs, cpioballs, or whatever. However, JPGs and > most movie formats will not compress well as they are already > compressed very heavily. So a full 2G backup will likely cost you 2G. > > There are a lot of factors involved and there is a lot more to setting > up a good backup regime than figuring out how much disk to throw at a > problem. Come the first disaster, they won't be your customer any more. ---- I understand this and I normally use bacula and am not familiar with backuppc but I gather that guessing that 90% of the files will not change in any given week, it will probably require less but I have no experience with backuppc Craig