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.