Talk presented by Florian Haas and Madison Kelly at LinuxCon Europe 2011, Prague, Czech Republic.

1. th
Attica, 5 century BCE.

2. No more than once a year,
and only if the Assembly so decided,
the citizens of Athens would gather
on Pnyx hill for a peculiar event.

3. Everyone had the option
of writing the name
of one fellow citizen
on a shard of pottery or earthenware.

4. The shards were counted,
and whoever received the most votes
had to leave the city
and was barred from returning
for 10 years unless recalled.

5. In Solonian democracy,
the process was believed to have
a cleansing effect on society
by removing those who misbehaved.

6. It was known as “ostrakismos”
(οστρακισμός), the root of
the modern English word ostracism.
In High-Availability clustering,
we call it fencing.

7. Fencing:
Putting things into a known state

9. WTF? NFI...
?
?
OK... RTFM!

10. Better. Much.
Tea, anyone? Totally.
?
?
Meh...

11. How can we fence?

12. Power fencing

13. ? bbl!
?

14. Fabric fencing

15. ?
? ugh.

16. Who fences? Callers

17. fenced
stonithd

18. What fences? Agents

19. IPMI
DRAC
iLO
RSA
Switched PDU
Meatware

20. Why is this important?

21. Storage Access

22. Locking

23. Stop Failure

24. What can go wrong?

25. After 10 years,
the banished person
was allowed to return.
His exile carried no stigma.

26. Rejoining

27. mkelly@iplink.net
florian@hastexo.com

28. https://alteeve.com
http://www.hastexo.com/shoutbox

29. Photo credits:
nath&mag
bazylek100
Titanas
Kostas Gerontis (Kokotron)