1. rsnapshot easy and automated backup/restore, snapshot style

2. This is not about

Backup strategy

• What and when

• overhead?

I just had a crash, please help me

3. Classic trade-off

Full backup

• Large backup time

• Quick and easy restore

• Space consuming

Incremental backups

• Quick backup

• Complex and time consuming restore

• More space efficient

4. rsnapshot

Combines full and incremental backups

• But off course only the good things

Quick backup process

Quick and easy restore

Space efficient

Remote, on harddisks, no tape switching

5. Amazing! But how?

I'll explain you!

6. Built on two key concepts

Rsync

Hardlinks

7. rsync

synchronizes files and directories

minimizing data transfer using delta encoding

optionally using compression and recursion.

daemon

native rsync protocol or SSH

free software

default on most UNIXs

8. Hardlinks

pointer to a file on a storage volume

more than one name can be associated with the same file

supported on UNIX's, Windows NT OS's

delete file = decrease link counter

• counter = 0: delete data

9. rsnapshot

Set of perl scripts

Calls rsync on regular base (cron)

• Only changed files transferred

• Local, remote, ssh,...

Creates hardlinks to unchanged files

• So every run delivers a full snapshot of the complete directory structure

• Only using diskspace of 1 full system + changes

• Restore: just copy the files/dirs of the snapshot

10. Practice: /etc/rsnapshot.conf

• Intervals

• • Interval daily 7

• • Interval weekly 4

• Exclude files

• Backup dirs

• • Backup /etc/ localhost/

• • Backup root@leffe:/data leffe/

• • Backup rsync://host/dir/ hostname/

• Backup scripts

• • backup_script /root/mysqlbackup_leffe.sh leffe/mysqlbackup/

11. My own little setup 12. My own little setup

WD MyBook = backup server

Daily, weekly, monthly backup

Wrapped in WoL script

Backup over SSH

• Secure?Root access?

• See next slide

Backupscripts: MySQL DB and dpkg package list

• Enables quick recovery of software on ubuntu/linux

13. SSH security

Non-interactive, only key-based login without passwords

Dedicated key for root

• In authorized_keys file on client

• IP-restriction: from="192.168.3.252"

• Command restriction: command="/root/validatescript"

• • Validatescript returnsoriginal commandorRejected

• • My setup: only rsync server, dpkg get-selections, pm-suspend and db-backup allowed

14. My experiences

WD MyBook is a very slow device (CPU)

• Possible optimisation: let script enable native rsync and disable after backup

First backup took some time

Daily (incremental) backups are quite fast

Watch out for rollback!

15. Conclusion

Quite easy and very extensible

More info:www.rsnapshot.org

more info on hacking WD: http://mybookworld.wikidot.com/

16. Thank you very much! Questions?