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I have a working server with a raid > lvm > dmcrypt stack. I would like a backup solution which solves the following problems:

  • Changes only: Only transfer daily change, not the whole X Terrabytes every time. (The ability keep different versions for X days is a plus but not a must).
  • Able to restore to disk(s) with different geometry: In case of a hardware failure I can not go out and buy the exact same type of hard drives (CHS characteristics) because they will be discontinued. I can buy same or bigger size though.

The problems I see:

  • Partitions: Copying the first 512 bytes (containing the Partition table) probably won't work on disks with different geometry, So I need some intelligent partition table backup solution.
  • Raid: partitions building up the raid are marked somehow (on the last sector of the partiton manybe?). This metadata needs to be restored on the new disks (a new raid should be built). So I need a solution which can rebuild a raid identical to the old one.
  • Grub: Besides the portions of GRUB in the MBR and /boot partition I suspect there are parts stored elsewhere (unused area in first cylinder of drive maybe). So when restoring I would need some custom GRUB installer (which will install the same version).
  • dm_crypt: before restoring the data, the encrypted partitions should be set up. Of course with prompting for keys when necessary.

Restrictions by the target:

  • Samba: I only have a samba share to deposit the data, so probably some additional utility (tar) should be used to keep special file flags and ownership.
  • Encryption: File level encryption (something like encfs) should be used on the local side, because I do not want unencrypted information leave the system.
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It feels like you're an admin with a windows background, because... Linux backups don't work like that. Obsessions with geometry and RAID and bootloaders aren't necessary, because Linux is far more flexible about that sort of thing. – womble Jul 9 '12 at 10:09
@womble The less of these problems apply in Linux the happier I am. But for example I'm using MS-DOS style partition table for compatibility reasons, so some things might apply though. I'm certainly new to LVM and dm-crypt, if there is any tool which can restore these structures out-of-the-box I'm open to suggestions. – vbence Jul 9 '12 at 14:03
So pardon the obvious/stupid question, but why don't you do this with scripted file-copies? You could take a "full" or a full disk image periodically and frequent "diffs" based on file modified date and have each "backup" job create a folder based on the date in your SAMBA share. – HopelessN00b Jul 13 '12 at 23:16
@HopelessN00b My biggest problem with images is that I'm not sure that a disk image restored to a different hard drive would result in a workable system. Can you please offer some literature concerning this topic? – vbence Jul 14 '12 at 20:20
@vbence: Can't provide literature on that because I'm not sure myself, especially with your mention of "using MS-DOS style partition table for compatibility reasons." (eek!) If I were in your shoes, the first thing I'd try would probably be scripted file backups (as I suggested), with some sort of base disk/base OS image I could fire up and dump those files into, in the event I needed to do a "restore." Wouldn't quite be a one-touch solution, but it would seem to take a lot of the requirements off the backups themselves, which might help you do what you're looking for. Hope that's helpful. – HopelessN00b Jul 18 '12 at 22:36

Duplicity provides incremental versioned backups (using rsync algorithm) and encrypted local storage, though I'm not sure how you'd handle backup of things like Grub, or RAID metadata, etc., if they're not straight filesystem backups.

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have a look a Asigra solution - it is incremental forever with de-duplication model. It is online backup service that can do everything you are asking for but I'm not sure if this model well work for you. There are plenty of providers around the world who provides service based on this platform. I'm using it myself and quite happy about feature set, pricing though may be an issue though.

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