Scaling MySQL in AWS

All Your Base Conf, Oxford, UK

Laine Campbell, Co-Founder

October 17th, 2014

Who am I?

DB Architect, Entrepreneur and super hero…Good hair, not overly clever, female pronouns

Who am I?

Humor - Self effacing, self aggrandizing, dry…Cajun, rogueish, and I destroy everything I touch...

Who am I?

When in doubt, laugh

Who am I?

Happy Belated Ada Lovelace Day

Agenda

● Amazon options for implementation● MySQL scaling patterns● Resiliency● Round it out● War Stories

RDS and EC2/MySQL

A love story...

Amazon RDS (DBaaS)

Basic Operations Managed

Ease of Deployment

Supports Scaling via Replication

Resilient via Replication, EBS RAID, Multi-AZ, Multi-Region

What is Multi-AZ?

Automatic Failover, spread across availability zones

Significantly reduces impact of operations such as:● Backups● Replica Builds● Patching

Managed Operations

● Backups and Recovery ● Provisioning ● Patching● Auto Failover● Replication

What does it cost?

● Instance tax: 35% - 37%● Provisioned IOPS: 15% ● Lack of transparency - can increase downtime

What does it cost?

● Multi AZ Master - db.r3.8xlarge, 1 yr reserved○ $17,312

● 3 replicas - b.r3.8xlarge, 1 yr reserved○ $25,968

● Provisioned IOPS - general purpose (new)○ 1 TB dataset = $6,144 (5 copies)

● Total Cost RDS = $49,424● Off of RDS = $34,726

Cost Thoughts

● RDS costs $14,698/yr ○ DBA costs $144K/yr, = $108 hour (time off, productivity,

retention/churn)○ Equals 136 hours of DBA time (3.5 weeks)

● Automating via EC2 is a one time job, RDS tax is ALWAYS○ 5 clusters costs you 680 hours of DBA time (17 weeks)○ 5 clusters, 3 years = 2,040 hours, or 51 weeks○ What can your DBA do with an extra 51 weeks?

Other Costs

● Lock-in:○ In 5.6, you can replicate out, making this moot.○ You have to automate once out, you could have spent

this in the beginning.● Lack of Visibility:

○ Dtrace, TCPDump, Top, VMStat, etc…● Lack of Control:

○ Data Security, Shared Environments, Backups????○ Restarts due to exploits, etc...

Amazon EC2, Roll Your OwnBuild your own automation:● Provisioning, with replication● Configuration management● Backup and recovery● Instance registration

Other DBaaS Options such as Tesora Trove● Community, free● Enterprise starts at $25,000 for 50 instances● don’t forget RDS, 5 clusters, 1 years = $73,440

Choosing RDS vs EC2

Why use RDS?

● Legacy apps that cannot use 5.6, and can accept < 99.65% SLAs

● Low volume/traffic applications for companies who choose to not have their own operations expertise

Why use EC2?

● Want MariaDB or XtraDB Variants● Want more flexibility in multi-region setups (before

5.6)● Want portability to other clouds● High performance and scale needs that require

access to the OS, and to the FULL DB instance

Storage Options in AWSType RDS EC2 Persistent Max

IOPSMax Throughput

Cost

Pure SSD No Yes No 100,000 390 MBps Free w/Instance Cost

EBS General Purpose SSD

Yes Yes Yes 3,000 128 MBps $.10/GB/month

EBS PIOPS SSD Yes Yes Yes 4,000 128 MBps $.125/GB/month + $.065/PIOPS/month

EBS Magnetic Yes Yes Yes 40-200 40-90 MBps $.05/GB/month + $.05/million IOPS

Scaling MySQL at AWS

My Definition of Scaling

● Capacity is elastic and automated● Performance stays reasonably consistent● Availability scales● Resiliency scales● Operational visibility scales● Backup and recovery scales

MySQL Workload Scaling

● Break out workloads to their own clusters○ To facilitate sharding large data-sets horizontally○ To segregate specific workload characteristics

● Evaluate each workload’s read/write needsTotal dataset size and growthData change delta (updates/deletes)

MySQL Workload Scaling

User Login/Profile1 TB (1MM User)20,000 iops peak10% write90% read

User Content5 TB500,000 iops peak1% write99% read

Site Metadata5 GB500 iops peak25% write75% readShard Candidate

Shard Candidate

MySQL Workload Scaling

Determine sharding size based on constraints○ AWS Write IO○ Replication Limits○ Tolerance for large numbers of systems○ Budget

MySQL Workload Scaling

Sharding Topology:● Schema:Shard relationship 1:1● Instance:Schema relationship 1:N● Host:Instance relationship 1:1

Host 1

Instance 1

Shard 1 Shard 2

MySQL Workload Scaling

User Profile Data - 10 shards, hashable○ Per Shard: 2,000 (500MB) iops, 200 wps (50MB), 100 GB storage

■ Two replication threads/shards per cluster○ SSD General Purpose EBS, 2 300 GB Volumes Striped (

■ 1,800 IOPS, 6000 burst, 800 MBps○ 3,600 rps (900 MBps) requires 2 replicas (500 MBps), +1 for

redundancy○ 1 master, 1 failover, 3 replicas = 25 hosts, r3.2x lg

■ Memory = 61 GB > active dataset■ Assumes read/write splitting

○ Total Cost = $48,600 instances + $18,000 storage = $66,600

MySQL Workload Scaling

Keep Schema:Shard relationship 1:1Change Schema:Instance relationship from 1:N to 1:1Change Instance:Host relationship from 1:1 to 1:N

Host 1

Instance 1

Shard 1

Instance 2

Shard 2

MySQL Workload Scaling

Summary○ Final Constraint is Write IOPS○ Sharding eliminates Constraint○ There are ways to reduce those reads:

■ Caching○ There are ways to reduce those writes:

■ Throttling concurrency with queuing and loose coupling to keep write IO down

■ Compression! Native or application based○ Moving storage to ephemeral SSD saves $$$$

■ If you truly can leverage backup and recovery with small datasets

MySQL Workload Scaling

Master

Replica Replica

Failover

Shard 1

Master

Replica Replica

Failover

Shard 2

Resiliency Layers

● Sharding○ Shard N = y% of traffic, where y = 1/Shards*100○ Aka with 64 shards, one shard lost = 1.56%

● EBS Snapshots○ Rapid redeployment of failed nodes (kill, rebuild)

Type of Change EC2 RDS Master(Non Multi-AZ)

RDS Master(Multi-AZ)

RDS Replica

Instance resize up/down

Rolling Migrations Moderate Downtime

Minimal Downtime

Moderate Downtime (take out of service)

EBS <-> PIOPS Severe Perf impact Severe Perf impact Minor Perf impact Severe Perf Impact (take out of service)

PIOPS Amount Change

Minor Perf impact Minor Perf impact Minor Perf impact Severe Perf Impact (take out of service)

Disk Space Change (add)

Severe Perf impact Severe Perf impact Minor Perf impact Severe Perf Impact (take out of service)

Disk Space Change (reduce)

Rolling Migrations Severe Downtime(promote from replica)

Minimal Downtime

Moderate Downtime (take out of service)

Power Up - Resiliency via Geography

MySQL Workload Scaling

S1 Master

Replica Replica

US East 1

S2 Failover

During failover, spawn replicas

US West 1

AZ 2 AZ 3

AZ 1

Future Replica

Future Replica

AZ 2 AZ 3

Nginx Nginx

Cluster Management and Failover

● Roll your own…. ○ Config Mgmt○ Automation Scripting○ HAProxy

● Spend some dough○ RDS○ Continuent Tungsten○ Scalearc

● Bleeding edge but clotting○ Galera, via MariaDB or XtraDB Cluster

● Bleeding edge and fresh○ Openstack, Trove and Tesora

Rounding it Out: Operational Visibility

● Monitoring and Alerting: Sensu (not Nagios)● Time Series Trending: Graphite or OpenTSDB● Graphing of Data: Grafana● Log Aggregation and Management: Logstash or Splunk● Application Monitoring: New Relic or AppDynamics

Rounding it Out: Backup and Recovery

● Sharding keeps systems small and agile○ Snapshots for tactical kill and build○ S3 for longer-term○ Glacier forever○ Offsite for Legal

Questions and Follow up

○ lcampbell@pythian.com○ www.pythian.com○ www.linkedin.com/lainecampbell○ www.adafoundation.org