Talk by Tom Wilkie at Cassandra EU

1. Next Generation
Cassandra
Tom Wilkie
Founder & VP Engineering, Acunu

3. Cassandra needs a team
• Installing, configuring and deploying
• Automating management operations
• Monitoring and alerting $ $ $
$
• Testing and fixing bugs
• Tuning the garbage collector
• Tweaking the storage engine
3

4. Acunu: your enterprise Cassandra Appliance
Data driven applications Web UI
Apache Cassandra
Control
Center
Acunu Storage Engine
Configured and tuned OS
Commodity Hardware
4

5. Storage Engine
aka Castle

6. Castle: Built for Big Data
• Storage engine optimized for large slow disks,
many cores, Big Data workloads
• Enterprise density on commodity hardware
• Lightning disk rebuilds:10x faster than RAID
Shared memory interface
Castle
keys
Userspace
Acunu Kernel
userspace
interface
values
In-kernel
async, shared
memory ring workloads
shared buffers
kernelspace
Streaming interface
interface
range key buffered key buffered
queries insert value insert get value get
Doubling Arrays • Opensource (GPLv2, MIT
doubling array
mapping layer
for user libraries)
insert Bloom filters
queues key
get
arrays x
range arrays
queries management
http://goo.gl/gzihe
key
•
insert merges
http://bitbucket.org/acunu
Arrays
mapping layer
•
modlist btree
key Version tree
Loadable Kernel Module,
insert btree
key
get
btree
targeting CentOS’s 2.6.18
range
queries value arrays
6
•
Cache
apping &
http://www.acunu.com/
ng layer
"Extent" layer
prefetc
extent block
extent cache

8. Rebuild time
5
4
Rebuild Time (Hours)
3
2
1
0 RAID10, 8 Disks RAID5, 8 Disks RDA, 8 Disks RDA, 15 Disks
8

9. Control Center
9

10. Control Center
The new UI has been critical in helping us work out what is wrong in our code
“The new UI has been critical in helping us work out
what is wrong in our code”
- Matt Miller, TellyBug

11. Breaking System

12. 13,000 tests per day
1.1 million tests per release
3.5k machine days of testing
for each release
12

13. Short, unit tests
Distributed tests
Data integrity tests
Tests for common, long running operations
(bootstrap, decommission, backup, restore etc)
Failure simulation
Resource usage tests
(checking memory and cpu consumption)
Long running performance tests
13

18. “Turnkey Cassandra”
No need to master the internals
No tuning required
No need for a committer on staff