Moxi is a memcached proxy that allows clients like PHP applications to connect to it instead of directly to memcached servers. It handles protocol conversion, failure handling, consistent hashing of keys, and GET deduplication to improve performance. Moxi can also act as a front cache and support configurable features like timeouts, blackhole mode, and fire-and-forget SET operations.

1. moxi
a memcached proxy

2. who
• steve yen
• dustin sallings
• matt ingenthron

3. rhymes with foxy

4. open source

5. multithreaded C

6. standing on the
shoulders of giants
• libmemcached
• memcached
• libevent

7. web stack
apache
php php php php
memcached memcached memcached

8. choose your weapons
apache
php RoR Django perl
memcached memcached memcached

9. php then...
apache
php php php php
memcached memcached memcached

10. connection mesh
apache
php php php php
memcached memcached memcached

11. moxi
apache
php php php php
moxi
memcached memcached memcached

12. moxi connections
apache
php php php php
moxi
memcached memcached memcached

13. moxi connections
apache
php php php php
moxi
memcached memcached memcached

14. moxi connections
apache
php php php php
moxi
configurable
concurrency
memcached memcached memcached

15. protocol conversion
apache
php php php php
ascii protocol
moxi
ascii protocol
memcached memcached memcached

16. protocol conversion
apache
php php php php
ascii protocol
moxi
ascii protocol
binary protocol
memcached memcached memcached

17. auth’ed connections
apache
php php php php
moxi
auth’ed
binary protocol
memcached memcached memcached

18. consistent hashing
apache
php php php php
moxi
memcached memcached memcached

19. consistent hashing
apache
php php php php
moxi
a new server!
memcached memcached memcached memcached

20. management channel
apache
php php php php
dynamic reconfigurations
and statistics moxi
a new server!
memcached memcached memcached memcached

21. GET de-duplication
get item:2421
get item:2421 get item:2421

22. GET de-duplication
apache
get a b c get b c d get c d e
moxi
get a b c d e instead of...
get a b c
memcached get b c d
get c d e

23. front cache
apache
php php php php
front cache
moxi
memcached memcached memcached

24. front cache
apache
php php php php
front cache
moxi
memcached memcached memcached

25. front cache
apache
php php php php
Prefix-based. For limited
number of hot items.
front cache Served without
moxi hitting wire.
Simple expirations.
Meant for replication
friendly content.
memcached memcached memcached

26. front cache
hot items replicated across many front caches.
moxi moxi moxi
memcached memcached memcached

27. front cache
hot items replicated across many front caches.
moxi moxi moxi
memcached memcached memcached

28. front cache
hot items replicated across many front caches.
lazily.
moxi moxi moxi
memcached memcached memcached

29. failure handling
moxi moxi moxi
memcached memcached memcached

30. failure handling
for hiccups: configurable retry counts.
then send misses and ERROR back to clients
moxi moxi moxi
memcached memcached memcached

31. failure handling
for deep failures (and for planned server changes)
dynamic reconfiguration messages
moxi moxi moxi
mgmt
channel
memcached memcached memcached memcached

32. failure handling
for deep failures (and for planned server changes)
dynamic reconfiguration messages
moxi moxi moxi
mgmt
channel
memcached memcached memcached memcached

33. draining and filling
lazily migrate items from old server to new server
moxi moxi moxi
mgmt
channel
memcached memcached memcached memcached
draining filling

34. draining and filling
N time later, just use filled server only
moxi moxi moxi
mgmt
channel
memcached memcached memcached memcached
drained filled

35. timeout

36. timeout
• if a request takes more than X millisecs,
moxi should return a miss or error

37. blackhole configuration
• GET’s become misses
• SET’s become error
• clients never wait, such as trying
to make a connection to a non-
existent memcached

38. fire & forget SET
client... moxi...
session[‘shopping-cart’] = user_cart;
sends... set session:123456 some_big_value
receives... set session:123456 some_big_value
sees a match with configurable prefix
“session:”
responds with STORED to client.
receives STORED. forwards to memcached
asynchronously.
continues on its way.

39. inside moxi
• memcached
• libevent
• libmemcached

40. inside moxi
memcached
hash item manager
table slabber
ascii binary
protocol protocol
handler handler
drive_machine
protocol state machine
libevent

41. inside moxi
memcached proxy
hash item manager libmemcached front
table slabber dyna-config matcher cache
ascii binary ascii proxy ascii proxy binary proxy
protocol protocol upstream downstream downstream
handler handler protocol handler protocol handler protocol handler
drive_machine
protocol state machine
libevent

42. inside moxi
memcached proxy
hash item manager libmemcached front
table slabber dyna-config matcher cache
ascii binary ascii proxy ascii proxy binary proxy
protocol protocol upstream downstream downstream
handler handler protocol handler protocol handler protocol handler
drive_machine
protocol state machine
libevent

43. moxi embeds memcached
memcached proxy
hash item manager libmemcached front
table slabber dyna-config matcher cache
ascii binary ascii proxy ascii proxy binary proxy
protocol protocol upstream downstream downstream
handler handler protocol handler protocol handler protocol handler
drive_machine
protocol state machine
libevent

44. moxi’s can talk to themselves
but, they think they’re talking to memcached
moxi moxi moxi

45. moxi’s can talk to themselves
and to memcached
and, they still think they’re talking to just memcached
moxi moxi moxi
memcached

46. moxi’s can talk to themselves
and to memcached
and, they still think they’re talking to just memcached
moxi moxi moxi
memcached memcached

47. moxi’s can talk to themselves
and to memcached
and, they still think they’re talking to just memcached
moxi moxi moxi
memcached memcached memcached

48. moxi’s can talk to themselves
and to memcached(*)
and, they still think they’re talking to just memcached
moxi moxi moxi
memcached tokyo memcachedb
tyrant

49. starting
moxi
memcached command
command-line line
• memcached -m 512
• moxi -m 512 -z [configkey]

50. when can I get moxi?

51. today
• upcoming features
• draining/filling - August 2009
• everything else is done
• Available Now

52. where can I get moxi?

53. links
• getting moxi
• http://labs.northscale.com/moxi
• read, join list
• moxi@googlegroups.com

54. support, training
• available from NorthScale, Inc.
• steve.yen@northscale.com
• 888.399.5509
• support@northscale.com

55. questions?

56. thanks!
photo credits
• http://flickr.com/photos/davebluedevil/15877348/
• http://www.flickr.com/photos/theamarand/2874288064/
• http://www.flickr.com/photos/splityarn/3469596708/
• http://www.flickr.com/photos/heisnofool/3241930754/
• http://www.flickr.com/photos/onourminds/2885704630/
• http://www.flickr.com/photos/lunaspin/990825818/

58. talking to itself
optimization

59. stats aggregation
broadcasts “stats”. sums the responses.
moxi
memcached memcached memcached

60. flush_all
broadcasts “flush_all” to memcached servers
moxi
memcached memcached memcached