[ntp:hackers] On converting to FreeBSD servers here

Mark Martinec Mark.Martinec at ijs.si
Wed Dec 22 15:52:18 PST 2004


> I assume Samba works with FreeBSD. I am building a monster archive
> machine (0.5 TB) intended as backup/restore should something break on
> another machine. What I need is a utility to checkpoint full disk images
> across the net for archive. I bet somebody here already does that.

One approach that I like for a FreeBSD system:
- freeze files / prepare a fs snapshot,
- duplicate hard links of the last backup copy,
- rsync the differences over the copied backup tree.



To do a snapshot of a running system:
(see: /usr/src/sys/ufs/ffs/README.snapshot
      http://www.mckusick.com/softdep/
      man 8 mount -> search for 'snapshot' )

then back it up across the network with rsync (/usr/ports/net/rsync/),
either using push or pull (with rsync daemon) method.

A useful technique to keep old snapshot versions and
let the file system automagically store only changed
data but use multiple hard links to unchanged data is to:
- copy the entire last backed up file tree (only inodes) by copying
  only hard links (pax -r -w -l, or using cpio),
- using rsync, let it back up the disk (only differences) across the
  newly made copy of the backup tree. The changed files will
  relinquish their link and obtain their own newer data storage,
  unchanged files in all backup sets will all point to the same
  data sectors.

Mark



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