Three use cases of Apache Cassandra in real-world implementations and the best practices distilled from such.

1. STAMPEDECON 2014
CASSANDRA
IN THE REAL WORLD
Nate McCall
@zznate
!
Co-Founder & Sr.Technical Consultant
!
Licensed under a Creative Commons Attribution-NonCommercial 3.0 New Zealand License

2. AboutThe Last Pickle.
!
Work with clients to deliver and improve
Apache Cassandra based solutions.
!
Based in New Zealand & USA.

3. “…in the Real World?”
!
Lots of hype,
stats get attention,
as do big names

4. “Real World?”
!
“…1.1 million client writes per second.
Data was automatically replicated across all
three zones making a total of 3.3 million
writes per second across the cluster.”
http://techblog.netflix.com/2011/11/benchmarking-cassandra-scalability-on.html

5. “Real World?”
!
“+10 clusters, +100s nodes,
250TB provisioned,
9 billion writes/day, 5 billion reads/day”
http://www.slideshare.net/jaykumarpatel/cassandra-at-ebay-cassandra-summit-2013

6. “Real World?”
!
…
• “but I don’t have an∞ AMZN budget”
• “maybe one day I’ll have that much data”

7. “Real World!”
!
Most folks needed:
real fault tolerance,
scale out characteristics

8. “Real World!”
!
Most folks have:
3 to 12 nodes with 2-15TB,
commodity hardware,
small teams

9. !
Cassandra at 10k feet
Case Studies
Common Best Practices
Cassandra in the Real World.

10. Cassandra Architecture (briefly).
API's
Cluster Aware
Cluster Unaware
Clients
Disk

11. Cassandra Cluster Architecture (briefly).
API's
Cluster Aware
Cluster Unaware
Clients
Disk
API's
Cluster Aware
Cluster Unaware
Disk
Node 1 Node 2

12. Dynamo Cluster Architecture (briefly).
API's
Dynamo
Database
Clients
Disk
API's
Dynamo
Database
Disk
Node 1 Node 2

13. Cassandra Architecture (briefly).
!
API
Dynamo
Database

14. APITransports.
!
Thrift
Native Binary

15. Thrift transport.
!
Extremely performant for
specific workloads
Astyanax,
disruptor-based HSHA in 2.0

16. APITransports.
!
Thrift
Native Binary

17. Native BinaryTransport.
!
Focus of future development
Uses Netty,
CQL 3 only,
asynchronous

18. API Services.
!
JMX
Thrift
CQL 3
!

19. API Services.
!
JMX
Thrift
CQL 3
!

20. API Services.
!
JMX
Thrift
CQL 3
!

21. Cassandra Architecture (briefly).
!
API
Dynamo
Database
Please see:
http://www.slideshare.net/aaronmorton/cassandra-community-webinar-introduction-to-apache-cassandra-12-20353118
http://www.slideshare.net/planetcassandra/c-summit-eu-2013-cassandra-internals
http://www.slideshare.net/aaronmorton/cassandra-community-webinar-august-29th-2013-in-case-of-emergency-break-glass

22. Cassandra in the Real World.
!
Cassandra at 10k feet
Case Studies
Common Best Practices

23. Case Studies.
Ad Tech
Sensor Data
Mobile Device Diagnostics

24. AdTech.
Latency = $$$

25. AdTech.
Large “Hot Data” set
active users,
targeting,
display count

26. AdTech.
Huge Long Tail
who saw what,
used for billing,
campaign effectiveness over time,
all sorts of analytics

27. AdTech: Software.
Java
CQL via DataStax Java Driver
Python
Pycassa (Thrift)

28. AdTech: Cluster.
Cluster
12 nodes,
2 datacenters,
{DC1:R1:3,DC2:R2:3}

29. AdTech: Systems.
Physical Hardware
commodity 1U 8xSSD,
36GB RAM,
10gigE + 4x1gigE

30. Case Studies.
AdTech
Sensor Data
Mobile Device Diagnostics

31. Sensor Data.
Latency != $$$

32. Sensor Data.
High Write Throughput:
consistent “shape”,
immutable data,
large sequential reads,
high uptime (for writes)

33. Sensor Data: Software.
REST application:
separate reader service,
writes to kafka,
ELB to multiple regions

34. Sensor Data: Software.
Java:
Thrift via Astyanax,
read from kafka and batch
insertions to optimal size

35. Sensor Data: Cluster.
Cluster
9 nodes,
1 availability zone,
{RF:3}

36. Sensor Data: Systems.
m1.xlarge:
15GB, 2TB RAID0
“high”,
tablesnap for backup

37. Case Studies.
AdTech
Sensor Data
Mobile Device Diagnostics

38. Device Diagnostics.
Latency = battery

39. Device Diagnostics.
Write Bursts
large single payloads,
large hot data set

40. Device Diagnostics.
Huge long tail
but irrelevant after 2 months,
external partner API*
!
*thar be dragons

41. Device Diagnostics: Software.
Java
CQL / DataStax Java Driver

42. Device Diagnostics: Software.
REST application
Payloads to S3,
pointer in kafka to payload

43. Device Diagnostics: Cluster.
Cluster
12 nodes,
3 availability zones
{us-east-1:1}

44. Device Diagnostics: Systems.
i2.2xlarge
61gb, 1.8TB RAID0 SSD
“Enhanced Networking”,
dedicated ENI

45. Device Diagnostics: Systems.
No Backups.
!
!

46. Device Diagnostics: Systems.
No Backups.
!
“Replay the front end.”

47. Cassandra in the Real World.
!
Cassandra at 10k feet
Case Studies
Common Best Practices

48. Common Best Practices.
API's
Cluster Aware
Cluster Unaware
Clients
Disk

49. Client Best Practices.
Decouple!
buffer writes for
event based systems,
use asynchronous operations

50. Client Best Practices.
Use Official Drivers
(but there are exceptions)

51. Client Best Practices.
CQL3:
collections,
user defined types,
tooling available

52. Common Best Practices.
API's
Cluster Aware
Cluster Unaware
Clients
Disk

53. API Best Practices.
Understand Replication!

54. API Best Practices.
Monitor & Instrument

55. Common Best Practices.
API's
Cluster Aware
Cluster Unaware
Clients
Disk

56. Cluster Best Practices.
Understand Replication!
learn all you can about
topology options

57. Cluster Best Practices.
Verify Assumptions:
test failure scenarios explicitly

58. Common Best Practices.
API's
Cluster Aware
Cluster Unaware
Clients
Disk

59. Systems Best Practices.
Better to have a lot of a little
commodity hardware*,
32-64gb or RAM (or more)
*10gigE is now commodity

60. Systems Best Practices.
BUT: do you have staff that
can tune kernels?
larger hardware needs tuning:
“receive packet steering”

61. Systems Best Practices.
EC2
SSD instances if you can,
UseVPCs, Deployment groups
and ENIs

62. Common Best Practices.
API's
Cluster Aware
Cluster Unaware
Clients
Disk

63. Storage Best Practices.
Dependent on workload
can mix and match:
rotational for commitlog and
system

64. Storage Best Practices.
You can mix and match:
rotational for commitlog and
system,
SSD for data

65. Storage Best Practices.
SSD
consider JBOD,
consumer grade works fine

66. Storage Best Practices.
“What about SANs?”

67. Storage Best Practices.
“What about SANs?”
!
NO.
!
(You would be moving a distributed system
onto a centralized component)

68. Storage Best Practices.
Backups:
tablesnap on EC2,
rsync (immutable data FTW!)

69. Storage Best Practices.
Backups:
combine rebuild+replay for
best results
(Bonus: loading production data to staging is
testing your backups!)

70. Thanks.
!

71. Nate McCall
@zznate
!
Co-Founder & Sr.Technical Consultant
www.thelastpickle.com