It is the ability of a system to handle a growing amount of traffic/data in a capable manner

1. Web ScalabilityWeb Scalability
www.folio3.com@folio_3

2. Scalability
 It is the ability of a system to handle a growing amount of
traffic/data in a capable manner
 How much system can grow
 How easy it is to increase capacity

3. Generation Time
Delivery Time
Scalability

4. Solutions
 Add hardware. More CPU and RAM to machine
 Vertical Scalability
 Costly
 Higher TCO
 Add another server
 Horizontal Scalability
 More reliable
 Less costly as compared to other options
 Maintenance cost is higher

5. Opportunity Areas
 Database
 Application
 Web Server
 Scripting Language
 Hardware
 Hosting

6. Database
 Query Optimization
 Log slow queries
 Check query plan to make sure indexes are used
 Indexes
 A lot of how-to's available
 MySQL Query Cache
 Performance Schema

7. Database
 Review default values
 Index buffers
 Innodb Buffer Pool
 Number of open tables
 Innodb vs MyISAM
 Speed up file system
 Per-table file for Innodb
 Keep RDBMS updated
 A lot of diagnostic tools available

8. phpMyAdmin Advisor

9. Database
 Load balancing
 Route read queries to slaves
 Write queries to Master
 Multi-master Architecture
 Offload Database server
 Sphinx, Solr
 Nosql (Radis, Mongo etc)
 MySQL Cluster
 Write intensive

10. Application
 Identify Bottleneck
 Newrelic
 xDebug
 Framework profiling tools

13. Application
 Use framework DB APIs
 Avoid custom queries
 It allows the use of plug-ins / extensions / modules
 Use Framework cache APIs
 Don’t by-pass framework or CMS
 Profile your code
 Time
 Memory
 Profile/Monitor third party services

14. Application
 Cache output
 Full page cache
 Can be done in:
 Application (Disk, memcache, apc etc)
 Proxy server (varnish, lightspeed)
 Very effective
 Wikipedia serves 85% cached content. Only 15% is fetched from DB
 Cache static files in memory
 Query Results Cache
 Reduces number of queries
 Reduce IO
 Avoid file_exists sort of checks
 Reduce file operations

15. Web Server
 Explore options
 Apache
 Nginx
 Litespeed
 Load balancing
 HAProxy
 Ldirector
 Varnish (define multiple backend)
 Nginx, Apache balancer modules
 Decide balancing strategy
 Round robin, Last used, Weighted
 Do heavy lifting in crons, message queues

17. Web Server
 Fine-tune web server
 Don’t rely on default configurations
 Make web server use multiple cores
 E.g worker_processes for nginx
 Check your specific server configuration
 KeepAlive sort of options
 A lot can be done

18. Scripting Language (php)
 Enable opcache
 APC
 Opcache in 5.5
 eAccelerator
 Fine-tune settings
 Real path cache
 Buffers
 Max memory per script
 Look for best practices for that language

19. Hardware
 Disk is the slowest part of the system
 Go for SSD
 Reduce IO
 Offload Extensive downloads
 Cloud files
 CDN
 File system optimizations
 Number of files in folder
 RAID

20. Hosting
 Cloud vs. Dedicated
 Cloud makes scaling easy
 Easy to add hardware
 Easy to build
 Cloud is cheaper as compared to dedicated hardware
 Easy to separate DB & Application server
 Avoid having control panels on servers
 Cloud has slight performance disadvantage
 Does not work well when it is raining.

21. Resources
 http://www.slideshare.net/mkherlakian/high-performance-php-scaling-and-
getting-the-most-out-of-your-infrastructure
 http://www.slideshare.net/mohamed_almasry_lamp/lamp-applications-
scalability-lamp-web-applications
 http://20bits.com/article/10-tips-for-optimizing-mysql-queries-that-dont-
suck