(BDT323) Amazon EBS & Cassandra: 1 Million Writes Per Second

© 2015, Amazon Web Services, Inc. or its Affiliates. All rights reserved.
Jim Plush Sr Director of Engineering, CrowdStrike
Dennis Opacki, Sr Cloud Systems Architect, CrowdStrike
October 2015
BDT323
Amazon EBS and Cassandra
1 Million Writes Per Second on 60 Nodes

An Introduction
to CrowdStrike
We Are CyberSecurity Technology Company
We Detect, Prevent And Respond To All Attack Types In Real Time,
Protecting Organizations From Catastrophic Breaches
We Provide Next Generation Endpoint Protection, Threat Intelligence & Pre &Post
IR Services
http://www.crowdstrike.com/introduction-to-crowdstrike-falcon-host/

CrowdStrike Scale
• Cloud-based endpoint protection
• Single customer can generate > 2 TB daily
• 500K+ events per second
• Multi-petabytes of managed data
© 2015. All Rights Reserved.

Truisms???
• HTTPS is too slow to run everywhere
• All you need is anti-virus
• Never run Cassandra on Amazon EBS

What is Amazon EBS?
EBS data volume
EBS data volume
/mnt/foo
/mnt/bar
EC2 Instance
 Network mounted hard drive
 Ability to snapshot data
 Data encryption at rest & in flight

Existing Amazon EBS Assumptions
• Jittery I/O a.k.a: Noisy neighbors
• Single point of failure in a region
• Cost is too damn high
• Bad volumes (dd and destroy)

A Recent Project: Initial Requirements
• 1PB of incoming event data from millions of devices
• Modeled as a graph
• 1 million writes per second (burst)
• Age data out after x days
• 95% write 5% read

We Tried
• Cassandra + Titan
• Sharding?
• Neo4J
• PostgreSQL, MySQL, SQLite
• LevelDB/RocksDB

We Have to Make This Work
Cassandra had the properties we needed
Time for a new approach?
© 2015. All Rights Reserved. http://techblog.netflix.com/2014/07/revisiting-1-million-writes-per-second.html

Number of Machines for 1PB
0.
450.
900.
1350.
1800.
2250.
I2.xlarge c4.2XL EBS

Yearly Cost for 1PB Cluster
0.
4.
8.
12.
16.
I2.xlarge-on demand I2.xlarge-reserved c4.2xl - on demand c4.2xl - reserved
Millionsof$
With Amazon EBS

Initial Launch
Date Tiered Compaction
…more details by Jeff Jirsa, CrowdStrike
Cassandra Summit 2015 - DTCS
http://www.slideshare.net/JeffJirsa1/cassandra-summit-2015-real-world-dtcs-for-operators

Initial Launch
• Cassandra 2.0.12 (DSE)
• m3.2xlarge 8 core
• Single 4TB EBS GP2 ~10,000 IOPS
• Default tunings

Performance Was Terrible
• 12 node cluster
• ~60K writes per second RF2
• ~10K writes per 8 core box
• We went to the experts

Cassandra Summit 2014
Family Search asked the
same question:
Where’s the bottleneck?
https://www.youtube.com/watch?v=Qfzg7gcSK-g

IOPS Available
0.
12500.
25000.
37500.
50000.
I2.xlarge c4.2xlarge

1.3K IOPS?

IOPS
I see you there,
but I can’t reach you!

The magic gates
opened…
We hit 1 million
writes per second
RF3 on 60 nodes

Testing Setup

Testing Methodology
• Each test run
• clean C* instances
• old test keyspaces dropped
• 13+TBs of data loaded during read testing
• 20 C4.4XL Stress Writers each with their own 1BB sequence

Cluster Topology
Stress Node
10 Instances
AZ: 1A
Stress Nodes
10 Instances
AZ: 1B
20 C* Nodes
AZ: 1A
20 C* Nodes
AZ: 1B
20 C* Nodes
AZ: 1C
OpsCenter

Amazon EBS

Cassandra Stress 2.1.x
bin/cassandra-stress user duration=100000m cl=ONE profile=/home/ubuntu/summit_stress.yaml ops(insert=1) no-warmup -pop
seq=1..1000000000 -mode native cql3 -node 10.10.10.XX -rate threads=1000 -errors ignore

PCSTAT - Al Tobey
http://www.datastax.com/dev/blog/compaction-improvements-in-cassandra-21
https://github.com/tobert/pcstat

Netflix Test - What is C* capable of?

Netflix Test
1+ million writes per second RF:3 3+ million local writes per second
NICE!

Netflix Test

Netflix Test
No dropped mutations, system healthy at 1.1M after 50 mins

Netflix Test
I/O util is not peggedCommit disk = steady!

Netflix Test
Low I/O wait

Netflix Test
95th Latency = Reasonable

Netflix Test - Read Fail
compression={'chunk_length_kb': '64', 'sstable_compression': 'LZ4Compressor'}
https://issues.apache.org/jira/browse/CASSANDRA-10249
Data Drive Pegged 

Reading Data
• 24-hour read test
• over 10 TBs of data in the CF
• sustained > 350K reads per
second over 24 hours
• 1M reads/per sec peak
• CL ONE
• 12 C4.4XL stress boxes

Reading Data

Reading Data
Not Pegged 

Reading Data
7.2ms 95th latency

180 less cores (45 less i2.xlarge instances)
• C4.4XL vs. i2.XLarge
24 hour test (sans data transfer cost)
• Netflix cluster/stress
• Cost: ~$6300
• 285 i2.xlarge $0.85 per hour
• CrowdStrike cluster/stress with Amazon EBS cost
• Cost: ~$2600
• 60 C4.4XL $0.88 per hour
VS Netflix Blog Post

• Our test was a single 10K IOPS volume
• More/bigger reads?
• PIOPS gives you as much throughput as you need
• RAID0 multiple Amazon EBS volumes
Read Notes with Amazon EBS
EBS Data
Volume
EBS Data
Volume
/mnt
/foo
/mnt/bar
EC2 Instance

What Unlocked Performance

Major Tweaks
• Ubuntu HVM types
• Enhanced networking
• Now faster than PV
• Ubuntu distro tuned for cloud workloads
• XFS Filesystem

Major Tweaks
Major Tweaks
• Cassandra 2.1
• Java 8
• G1 Garbage Collector

Major Tweaks
• C4.4XL 16 core, EBS Optimized
• 4TB, 10,000 IOPS EBS GP2 Encrypted Data Drive
• 160MB/s throughput
• 1TB 3000 IOPS EBS GP2 Encrypted Commit Log Drive

Major Tweaks
cassandra-env.sh
• MAX_HEAP_SIZE=8G
• JVM_OPTS=“$JVM_OPTS —XX:+UseG1GC”
• Lots of other minor tweaks in crowdstrike-tools

cassandra-env.sh
Put PID in batch mode
Mask CPU0 from the process to reduce context switching
Magic From Al Tobey

YAML Settings
cassandra.yaml (based on 16 core)
• concurrent_reads: 32
• concurrent_writes: 64
• memtable_flush_writers: 8
• trickle_fsync: true
• trickle_fsync_interval_in_kb: 1000
• native_transport_max_threads: 256
• concurrent_compactors: 4

cassandra.yaml
We found a good portion of the CPU load was
being used for internode compression which
reduced write throughput
internode_compression: none

Lessons Learned
• Amazon EBS was never the bottleneck during testing, GP2 is legit
• Built-in types like list and map come at a performance penalty
• 30% hit on our writes using Map type
• DTCS is very young (see Jeff Jirsa’s talk)
• 2.1 Stress Tool is tricky but great for modeling workloads
• How will compression affect your read path?

Test Your Own!
https://github.com/CrowdStrike/cassandra-tools

It’s Just Python
launch 20 nodes in us-east-1
• python launch.py launch --nodes=20 —config=c4-ebs-hvm
—az=us-east-1a
bootstrap the new nodes with C*, RAID/Format disks, etc…
• fab -u ubuntu bootstrapcass21:config=c4-highperf
run arbitrary commands
• fab -u ubuntu cmd:config=c4-highperf,cmd="sudo rm -rf
/mnt/cassandra/data/summit_stress"

Run Custom Stress Profiles… Multi-Node Support
ubuntu@ip-10-10-10.XX:~$ python runstress.py --profile=stress10 —seednode=10.10.10.XX —-threads=50
Going to run: /home/ubuntu/apache-cassandra-2.1.5/tools/bin/cassandra-stress user duration=100000m cl=ONE
profile=/home/ubuntu/summit_stress.yaml ops(insert=1,simple=9) no-warmup -pop seq=1..1000000000 -mode native cql3 -node
10.10.10.XX -rate threads=50 -errors ignore
ubuntu@ip-10-10-10.XX:~$ python runstress.py --profile=stress10 --seednode=10.10.10.XX --threads=50
Going to run: /home/ubuntu/apache-cassandra-2.1.5/tools/bin/cassandra-stress user duration=100000m cl=ONE
profile=/home/ubuntu/summit_stress.yaml ops(insert=1,simple=9) no-warmup -pop seq=1000000001..2000000000 -mode native cql3
-node 10.10.10.XX -rate threads=50 -errors ignore
export NODENUM=1
export NODENUM=2

• ~3 months on our Amazon EBS–based cluster
• Hundreds of TBs of graph data and growing in C*
• Billions of vertices/edges
• Changing perceptions?
• DataStax - Planning an Amazon EC2 cluster
Where Are We Today?

Al Tobey’s Tuning Guide for Cassandra 2.1
https://tobert.github.io/pages/als-cassandra-21-tuning-
guide.html
Resources

Special Thanks To
Leif Jackson
Marcus King
Alan Hannan
Jeff Jirsa
• Al Tobey
• Nick Panahi
• J.B. Langston
• Marcus Eriksson
• Iian Finlayson
• Dani Traphagen

Amazon EBS Heading Into 2016

4TB (10k IOPS) GP2
I/O Hit? Not enough to phase C*

So why the hate for
Amazon EBS?

• Used instance-store image and
ephemeral drives
• Painful to stop/start instances, resize
• Couldn’t avoid scheduled maintenance
(i.e., Reboot-a-palooza)
• Encryption required shenanigans
Following the Crowd – Trust Issues

• We still had failures
• Now we get to rebuild from scratch
Guess What

What do you mean my volume is “stuck”?
• April 2011 – Netflix, Reddit, and Quora
• October 2012 – Reddit, Imgur, Heroku
• August 2013 – Vine, Airbnb
Amazon EBS’s Troubled Childhood

http://techblog.netflix.com/2011/04/lessons-
netflix-learned-from-aws-outage.html
Spread services across multiple regions
Test failure scenarios regularly (Chaos Monkey)
Make Cassandra databases more resilient by
avoiding Amazon EBS
Kiss of Death

Amazon moves quickly and quietly:
• March 2011 – New Amazon EBS GM
• July 2012 – Provisioned IOPs
• May 2014 – Native encryption
• Jun 2014 – GP2 (game changer)
• Mar 2015 – 16TB / 10K GP2/ 20K PIOPS
Redemption

• Prioritized Amazon EBS availability and consistency beyond
features and functionality
• Compartmentalized the control plane – removed cross-AZ
dependencies for running volumes
• Simplified workflows to favor sustained operation
• Tested and simulated via TLA+/PlusCal - better understood
corner cases
• Dedicated a large fraction of engineering resources to reliability
and performance
Redemption

Amazon EBS team targets 99.999%
availability
exceeding expectations
Reliability

• In past 12 months, zero Amazon EBS–
related failures
• Thousands of GP2 data volumes (~2PB
data)
• Transitioning all systems to Amazon EBS
root drives
• Moved all data stores to Amazon EBS
(C*, Kafka, Elasticsearch, Postgres, etc.)
CrowdStrike Today

• Select a region with >2 AZs (e.g.,
us-east-1 or us-west-2)
• Use Amazon EBS GP2 or PIOPs storage
• Separate volumes for data and commit
logs
Staying Safe - Architecture

• Use Amazon EBS volume monitoring
• Pre-warm Amazon EBS volumes?
• Schedule snapshots for consistent backups
Staying Safe - Ops

• Challenge assumptions
• Stay current on AWS blog
• Talk with your peers
Most Importantly
http://aws.amazon.com/ebs/nosql/

Remember to complete
your evaluations!
BDT323

(BDT323) Amazon EBS & Cassandra: 1 Million Writes Per Second

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(BDT323) Amazon EBS & Cassandra: 1 Million Writes Per Second