1.
Growing X20 without
spending an extra
penny on hosting
Dor Kalev, CTO @ FTBpro

2.
Largest fan-generated media platform in
global football
130m pageviews / month

3.
a Football fan #musthave
1M+ mobile installs

4.
Content is king

5.
Single Page Application
Phantom.js renders pages on the server-side for SEO,
crawlers and mobile web performance
Load Balancer
Memcached
Redis
Web 1 Web 2 Web 3
MySQL MongoDB ElasticSearch
Amazon Web Services
NginX
+
Ruby on
Rails
PhantomJS
Web 4

6.
How do we scale
post pages?

7.
Each Render Server can return
1 client request at a time
1:1
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Server
Render

8.
Linear correlation between
clients and servers
1:1
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Render

9.
A cache server can handle
over x10 more traffic
10:1:1
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10.
Cache server still consumes CPU and
with more traffic, more servers are needed
20:2:1
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11.
Accelerator like NGINX+MemCached or
Varnish can be x100 more efficient than
plain App Server Cache
100:1:1
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Accelerator
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https://www.igvita.com/2008/02/11/nginx-and-memcached-a-400-boost/
https://www.varnish-cache.org

12.
200:2:1
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Accelerator
Accelerator
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Accelerator also runs on limited hardware
and needs more CPU in order to scale

13.
Enter CDN
∞:1
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CDN
Server
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14.
Client
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My
Tiny
Server
PoP
CDN
SERVER
CDN
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CDN
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PoP
CDN
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CDN
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CDN
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PoP
CDN
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CDN
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What’s a CDN?

15.
What’s a CDN?
• Content Delivery Network
• A set of autonomic distributed cache servers
• Serve cache from a location geographically
close to the client
• e.g: Akamai, Cloudflare, Fastly, Highwinds,
Edgecast, Cloudfront

16.
Enter Trouble
∞:1
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CDN
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17.
Fixing minor Typo?
Need to Refresh Cache??

18.
TTL vs. ON CHANGE
Cache Policy

19.
Purge by URL can take over an
hour on classic CDNs
Z
Z
Z

20.
Purge by TTL - isn’t realtime &
causes redundant server hits
CPULOAD
0
7.5
15
22.5
30
TIME
1 2 3 4 5 (TTL) 6 7 8 9 (TTL) 10 11 12

21.
multiply by all articles
CPULOAD
0
7.5
15
22.5
30
TIME
1 2 3 4 5 (TTL) 6 7 8 9 (TTL) 10 11 12

22.
TTL = Constant waste of CPU
CPULOAD
0
7.5
15
22.5
30
TIME
1 2 3 4 5 6 7 8 9 10 11 12

23.
Better Solution?

24.
abuse new CDN
technologies
Super Fast Purge + Smart API!
!
!
!
!
!
e.g. Fastly, EdgeCast

25.
cache forever +
purge on demand
0
7.5
15
22.5
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1 (release) 2 3 4 5 6 7 8 9 (purge) 10 11 12

26.
fast purge at ~10-45 seconds

27.
Advantages
• ∞ scaling
• cheap
• fast
• keep the stack simple

28.
Caveats
• Purging everything can lead to downtime, e.g.
when deploying
• User Specific content can’t be cached with the
entire page
• Downtime on massive Push Notifications

29.
Massive Push Notification + cold CDN
Cache = traffic goes to app servers
CPULOAD
0
250
500
750
1000
TIME
1 (PN) 2 3 4 5 6 7 8 9 10 11 12

30.
Client
Client
My
Tiny
Server
PoP
CDN
SERVER
CDN
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CDN
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PoP
CDN
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CDN
SERVER
CDN
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PoP
CDN
SERVER
CDN
SERVER
CDN
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Client Client Client Client
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Render (or cache & serve) X number of calls
in parallel = self-DDoS

31.
Client
Client
CACHE
PoP
CDN
SERVER
CDN
SERVER
CDN
SERVER
PoP
CDN
SERVER
CDN
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CDN
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PoP
CDN
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CDN
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CDN
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Solution: Another local cache layer & Preload CDN
(few CDNs have this feature, e.g. EdgeCast)
My
Tiny
Server

32.
CPU vs TRAFFIC
• 13:53 preloaded post to CDN
• 13:55 PN sent
• 13:57+ traffic stops @ CDN servers, no CPU throughput
• 14:00 …

33.
14:00 Laugh a maniacal laugh of satisfaction

34.
Summary
• CDN allows massive scale
• Smart CDN usage allows even more scale
• Scale + fresh content + low hosting prices is a
do-able mission
!
Questions?

35.
Read More…
• Growing X20 without spending an extra penny on
hosting (The original blog post)
http://tech.ftbpro.com/post/78969626647/growing-x20-without-spending-an-extra-penny-on-hosting
• Single Page Applications Done Right
http://tech.ftbpro.com/post/84720180206/single-page-applications-done-right
• Count von Count - Real time counting DB
http://tech.ftbpro.com/post/73212710968/count-von-count-a-real-time-counting-database
• The Dark Side of Single Page Applications
http://tech.ftbpro.com/post/66182501420/the-dark-side-of-single-page-applications-rails
OSS: http://github.com/ftbpro
BLOG: http://tech.ftbpro.com