On 3/2/2010 10:15 AM, Kjetil Torgrim Homme wrote: > "valrh...@gmail.com" <valrh...@gmail.com> writes: > > >> I have been using DVDs for small backups here and there for a decade >> now, and have a huge pile of several hundred. They have a lot of >> overlapping content, so I was thinking of feeding the entire stack >> into some sort of DVD autoloader, which would just read each disk, and >> write its contents to a ZFS filesystem with dedup enabled. [...] That >> would allow me to consolidate a few hundred CDs and DVDs onto probably >> a terabyte or so, which could then be kept conveniently on a hard >> drive and archived to tape. >> > it would be inconvenient to make a dedup copy on harddisk or tape, you > could only do it as a ZFS filesystem or ZFS send stream. it's better to > use a generic tool like hardlink(1), and just delete files afterwards > with > > There is a perl script floating around on the internet for years that will convert copies of files on the same FS to hardlinks (sorry I don't have the name handy). So you don't need ZFS. Once this is done you can even recreate an ISO and burn it back to DVD (possibly merging hundreds of CD's into one DVD (or BD!). The script can also delete the duplicates, but there isn't much control over which one it keeps - for backupsyou may realyl want to keep the earliest (or latest?) backup the file appeared in.
Using ZFS Dedup is an interesting way of doing this. However archiving the result may be hard. If you use different datasets (FS's) for each backup, can you only send 1 dataset at a time (since you can only snapshot on a dataset level? Won't that 'undo' the deduping? If you instead put all the backups on on data set, then the snapshot can theoretically contain the dedpued data. I'm not clear on whether 'send'ing it will preserve the deduping or not - or if it's up to the receiving dataset to recognize matching blocks? If the dedup is in the stream, then you may be able to write the stream to a DVD or BD. Still if you save enough space so that you can add the required level of redundancy, you could just leave it on disk and chuck the DVD's. Not sure I'd do that, but it might let me put the media in the basement, instead of the closet, or on the desk next to me. -Kyle _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
