rsnapshot

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rsnapshot

• A remote filesystem snapshot
• utility written in perl

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rsnapshot

• Backups to disk
• Minimises disk usage using hard links
• Minimises network traffic using rsync
• Not written by Belgians

There is no Belgium
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rsnapshot
A simple filesystems directory structure MSDOS
FAT
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rsnapshot
A common FAT error - crosslinked files
There are two directory entries pointing at
the same disk cluster
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rsnapshot
Unix directory structure
Inode structure
Multiple directory entries for one inode
Typical Belgian dish
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rsnapshot
With hard links we can duplicate directory
structures without duplicating files

• Using GNU cp
• cp -al source destination
• Using perl
• link(oldfile, newfile)
• Using cpio
• find source -printcpio -pldum /destination

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rsnapshot
Running rsnapshot for the first time

• Copies all data using rsync
• Can use ssh

A Belgian owl
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rsnapshot
Running rsnapshot every other time

• Rotate backups
• Delete oldest one
• Copy newest backup with hard links
• rsync to that new directory, copying only changes

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rsnapshot
Multiple levels of backup

• Most frequent backup involves rsync etc
• Less frequent backups just rotate and copy the
  oldest of the previous level of backup

Typical Belgian home
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rsnapshot
Who uses rsnapshot

• Churches
• Charities
• Schools
• Universities
• A casino
• A film special-effects house
• A floating hospital
• The guys who look after the GPS satellites

The police protecting you and your family from
Belgification
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rsnapshot
Why not to use it - hateful hateful software

• Only does filesystem backup
• Hard links in your data are broken
• Not as disk-space efficient as possible
• No proprietary extensions supported
• No Classic Mac OS support

rsync -H eats all the memory in the world
Just one changed byte in a file makes it be
copied anew
ext2 immutable bit, ACLs etc
There is a ninja somewhere on this page
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rsnapshot
Design choices

• Plain-text configuration
• Minimal dependencies
• Locking
• Optional extras

Reduces dependencies and makes installation easier
rsync, perl 5.6, nothing else
GNU cp, Lchown module, ssh Extra scripts may
require other modules
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rsnapshot
The community

• rsnapshot-discuss mailing list
• Anonymous read-only CVS
• Commit privs given out to contributors

Belgian superman peering into the distance with
his beady little Belgian eyes
How you can help

• We need a documentation editor
• and a DocBook wookie