Presented by Daniel Coupal, Technical Services Engineer, MongoDB Experience Level: Introductory In his two years as a Technical Support Engineer, Daniel has worked with hundreds of MongoDB customers. Daniel will take you on a ride through some of his most memorable customer stories, told through the plots of your favorite Hollywood films. Get to hear about some of more unusual MongoDB use cases, the idiosyncratic choices behind them, and their path to success. You'll laugh, you'll cry, and you'll save yourself from making the common mistakes.

2. MongoDB Support Cases:
The Blockbusters
Daniel Coupal
Technical Services Engineer
Palo Alto

3. 3
Support Team

4. 4
Goal of the Presentation
• Remember 3 things from this presentation
• Make 1 change in your application or
deployment
• Good return on your hour spent in this
presentation

5. 5
#1 - “Toto, I've a feeling we're not in Kansas
anymore”

6. 6
#1 - “Toto, I've a feeling we're not in Kansas
anymore”
ü The Wizard of OZ (1939)

7. 7
#1 – The NoSQL World is different

8. 8
#1 – The NoSQL World is different
Relational World NoSQL World
1 - Model the data 1 - Define the access to the data
2 - Write the queries to access the
data
2 - Model the data

9. 9
#2 - “Houston, we have a problem”

10. 10
#2 - “Houston, we have a problem”
ü Apollo 13 (1995)

11. 11
#2 – Have a Test Environment
• Best
– identical cluster
– restore production data in test/staging/QA
environment
• Acceptable
– less shards with identical hardware
• Less desirable
– smaller hardware
– non representative data

12. 12
#3 – “Elementary, my dear Watson”

13. 13
#3 – “Elementary, my dear Watson”
ü The Adventures of Sherlock Holmes
(1905, 1921, 1939, 1984)

14. 14
#3 – Look for Clues of Bad Queries
(slow queries in mongod log)
• 2.6 format
• 2015-09-23T07:06:15.465-0400 [conn21987] query mydb.coll1
query: { tr: { $lte: "2014-08-24-day" }, a: "", b: "min" } planSummary:
COLLSCAN ntoreturn:0 ntoskip:0 nscanned:13798085
nscannedObjects:13798085 keyUpdates:0 numYields:267371
locks(micros) r:105591398 nreturned:0 reslen:20 812656ms
• 3.0 format
• 2015-10-15T19:48:15.095+0000 I QUERY [conn1844] query
mydb.coll2 query: { $readPreference: { mode: "primary" }, $query:
{key: "ZrzfmfFlUV3i8iARTyXWD0Qxa8I=" } } planSummary:
COLLSCAN ntoskip:0 nscanned:0 nscannedObjects:83256
keyUpdates:0 writeConflicts:0 numYields:650 nreturned:0 reslen:20
locks:{ Global: { acquireCount: { r: 1302 } }, Database:
{ acquireCount: { r: 651 } }, Collection: { acquireCount: { r: 651 } } }
121ms

15. 15
#3 – Look for Clues of Bad Queries
• mtools for plots and stats on queries

16. 16
#3 – Look for Clues of Bad Queries
• CloudManager
– Suggested indexes

17. 17
#4 - “Round up the usual suspects”

18. 18
#4 - “Round up the usual suspects”
ü Casablanca (1942)

19. 19
#4 – Settings in Production Notes
• Hardware
– Using NAS
– Using other FS than xfs on Linux for Wired Tiger
– Using other FS than ext4 or xfs on Linux for MMapV1
– Maxed out spinning disks
• OS Settings
– ulimits too low
– too high readahead for disks
– Transparent Huge Pages on
– NUMA on

20. 20
#4 – Settings in Production Notes
• Tools
– Production notes
– Mdiag (in Github)

21. 21
#5 - “You’re gonna need a bigger boat”

22. 22
#5 - “You’re gonna need a bigger boat”
ü Jaws (1975)

23. 23
#5 –Appropriate Hardware for OpsManager
• Correctly sizing right at the beginning
– Consulting package
– Open a Commercial Support ticket
• Beware of changes in the initial estimates

24. 24
#6 - “Bond, James Bond”

25. 25
#6 - “Bond, James Bond”
ü Dr. No (1962)

26. 26
#6 - Cloud/Ops ManagerAgents always
initiate communications
db.movies.find({“series”:”James Bond”})
.sort({“date”:1})
.limit(1)

27. 27
#6 - Cloud/Ops ManagerAgents always
initiate communications
Agent
Hi, I am part of the 007 group.
Server
Go collect information about the hosts
goldfinger, scaramanga and doctorno.
Agent
Here are their status and metrics for goldfinger
and scaramanga.
Agent
doctorno is now permanently unreachable.

28. 28
#7 – “You've got to ask yourself one question:
'Do I feel lucky?’“

29. 29
#7 – “You've got to ask yourself one question:
'Do I feel lucky?’“
ü Dirty Harry (1971)

30. 30
#7 - Knowledge is King
• Use the right resources
– MongoDB.com/presentations
– Conferences: MongoDB Days/MongoDB World
– Consulting packages
– Commercial Support
– Free Support (Google groups and Stack Overflow)
– Training classes

31. Conclusion

32. 32
Take Away
• Remember 3 things from this presentation
• Make 1 change in your application or
deployment
• Good return on your hour spent in this
presentation

33. Questions…
“You talking to me?”

34. Thank you
and
“May the Force be with you”