This document summarizes strategies for horizontally scaling a WordPress site. It discusses adding more servers to distribute load, including adding web servers, database servers, storage servers and load balancers. It also covers topics like database replication, shared storage, caching, logging, monitoring, email delivery and containerization. The goal of horizontal scaling is to improve availability, fault tolerance and cost efficiency compared to vertical scaling of a single server.

1. Scaling out
with WordPress
Konstantin Kovshenin

3. Shared Hosting

4. Shared Hosting

5. Shared Hosting

6. Shared Hosting
Web Server
Database Server
Mail Server

7. Making Changes
File Manager
WordPress Dashboard
FTP/SSH

9. Vertical Scaling
More CPU
More RAM
More Disk

10. Dedicated, VPS

11. But we’re in the
CLOUD now!
Same sh*t…

12. Vertical Scaling
Easy
Downtime
Physical limitations
Some things don’t scale
One server

13. Horizontal Scaling

15. Just

16. Just add

17. Just add more

18. Just add more SERVERS!

19. Horizontal Scaling
Less limitations
High availability & fault tolerance
Cost efficiency
Complexity

22. Web Server
Web Server

23. Database Server
dev.mysql.com
mariadb.org

24. Primary
Replica
dev.mysql.com/doc/refman/8.0/en/replication.html
mariadb.com/kb/en/standard-replication

25. Database
HyperDB
LudicrousDB
ProxySQL
MaxScale
github.com/automattic/hyperdb
github.com/stuttter/ludicrousdb
proxysql.com/
mariadb.com/kb/en/maxscale/

27. en.wikipedia.org/wiki/Network_File_System
gluster.org
ceph.io
github.com/humanmade/S3-Uploads
github.com/s3fs-fuse/s3fs-fuse
aws.amazon.com/storagegateway/file/s3/
Media
NFS
GlusterFS
Ceph
S3 / S3 Uploads / FUSE / Gateway

28. Load Balancer

30. nginx.org
haproxy.org
varnish-cache.org
Load Balancing
Nginx
HAProxy
Varnish

31. 2x Load Balancers
2x Web Servers
2x Database Server
2x Storage Servers

32. github.com/features/actions
circleci.com
capistranorb.com
ansible.com
fabfile.org
aws.amazon.com/codestar
cloud.google.com/build
Deployment
GitHub Actions, CircleCI
Capistrano, Ansible, Fabric
AWS CodeBuild, CodeDeploy
Google Cloud Build/Deploy

33. Backups
Source control
Shared storage backups
Database snapshots
Configuration backups

34. vs
£200
£1600

35. vs
£200
£1600

36. Latency

37. Scalability ≠ Performance

38. vs
£200
£1600
1 RPM

39. vs
£200
£1600
50k RPM

40. Object Caching
Redis
Memcache
2x
github.com/pantheon-systems/wp-redis
github.com/Automattic/wp-memcached

41. Page Caching
Batcache
Cache at LB
Cache at CDN
github.com/Automattic/batcache
nginx.org/en/docs/http/ngx_http_proxy_module.html

42. Cron Jobs
Cavalcade
ActionScheduler
1x
github.com/humanmade/Cavalcade
actionscheduler.org

43. Emails
Postfix
Exim
Amazon SES
1x
postfix.org
exim.org
aws.amazon.com/ses

44. elastic.co/elastic-stack
Logging
Elasticsearch
Logstash
Kibana
3x

45. newrelic.com
grafana.com/products/cloud
datadoghq.com
grafana.com/oss
nagios.org
munin-monitoring.org
Monitoring
Grafana
Nagios
Munin
1x
New Relic
Grafana Cloud
Datadog

46. cloud.google.com/logging
learn.microsoft.com/en-us/azure/azure-monitor/overview
aws.amazon.com/cloudwatch
Cloud
Google Cloud Logging
Microsoft Azure Monitor
Amazon CloudWatch

47. Containers

49. Just

50. Just add

51. Just add more

52. Just add more CONTAINERS!

53. Getting Started
VirtualBox
KVM, virt-manager
XenServer
Docker Compose, Minikube
virtualbox.org
en.wikipedia.org/wiki/Kernel-based_Virtual_Machine
virt-manager.org
xenserver.com
docs.docker.com/compose
minikube.sigs.k8s.io/docs

54. kovshenin@gmail.com
konstantin.blog
humanmade.com
Photos from unsplash.com
Icons from flaticon.com

55. fin