Introduction to different methods that can be used to separate out complex web systems and make them capable of supporting large scale data.

1. dealing with enterprise level data
posh term for ‘lots of’

2. Today we are looking at:
•Tier architecture and cloud computing
•Moving from 3-tier to n-tier
•Scaling services up for use in Enterprise web
•Caches
•Proxies
•Load Balancing
•Queueing

3. tier architecture and
cloud computing

4. Presentation
Logic
Business Logic
Data Access
Logic
Database
1 tier architecture
• All 3 layers are kept on the same machine
• Presentation, logic, and data are highly connected
• Bad for scalability (single processor being used
• Bad for portability
• Bad for maintenance (change one thing…change them all)

5. Presentation
Logic
Business Logic
Data Access
Logic
Database
2 tier architecture
Client Server
• Database runs on server
• Easy if you want to switch to a new database
• Presentation and logic still tightly connected
• Bad for server load
• Bad if you want to make changes

6. Presentation
Logic
Business Logic
Data Access
Logic
Database
3 tier architecture
Client Server
• Every layer can be on a different machine
• Presentation, logic, and data are all disconnected
DB Server

7. Presentation
Logic
Business Logic
Data Access
Logic
Database
3 tier architecture
Client Server
• Provides the user interface
• Handles interaction with the user
• Should not contain any business logic
DB Server

8. Presentation
Logic
Business Logic
Data Access
Logic
Database
3 tier architecture
Client Server
• Contains rules for processing information
• Should not contain any presentation information
• Can accommodate many users
DB Server

9. Presentation
Logic
Business Logic
Data Access
Logic
Database
3 tier architecture
Client Server
• Data storage layer
• Manages access to information
DB Server

10. Presentation
Logic
Business Logic
Data Access
Logic
Database
3 tier architecture
Client Server DB Server
HTML
CSS
JAVASCRIPT
PHP
ASP.NET
JAVA
javascript(ish)
SQL
MONGODB

11. Easier to maintain
Components are reusable
Faster division of work
Web Designer does presentation
Software Engineer does logic
DB Man does DB things…

12. moving from 3-tier
to n-tier

13. Availability
Performance
Reliability
Scalability
Managability
Cost

14. Availability
Performance
Reliability
Scalability
Managability
Cost
Services must be available all
the time, no matter what

15. Availability
Performance
Reliability
Scalability
Managability
Cost
Services must be super fast, no
lag time for users

16. Availability
Performance
Reliability
Scalability
Managability
Cost
Services must be reliable. The
data that is returned must be
the same every time it is called
on

17. Availability
Performance
Reliability
Scalability
Managability
Cost
Services must be easily
upgradable to make space for
additional content

18. Availability
Performance
Reliability
Scalability
Managability
Cost
Services must be easy to
manage, and should not break
anytime someone touches it

19. Availability
Performance
Reliability
Scalability
Managability
Cost
Services should be cost
efficient, in terms of the money
to create it and also the time
that it takes to create

20. As good as this is…it wont work for a big web system

21. Server Storage
Upload Image
Files written
to storage
Request Image
Client Computer
Image Located
Image Sent

22. Server Storage
Upload Image
Files written
to storage
Request Image
Client Computer
Image Located
Image Sent
make functions to separate services in
order to aid in scalability

23. Image
Write
Service
Storage
Upload Image
Files written
to storage
Request Image
Client Computer
Image Located
Image Sent
Image
retrieval
service

24. Image
Write
Service
Storage
Upload Image
Files written
to storage
Request Image
Client Computer
Image Located
Image Sent
Image
retrieval
service
build in redundancy to safeguard data

25. Image
Write
Service
Storage
Upload Image
Files written
to storage
Request Image
Client Computer
Image Located
Image Sent
Image
retrieval
service
Backup
Storage
Located in
another
geographical
location

26. Image
Write
Service
Storage
Upload Image
Files written
to storage
Request Image
Client Computer
Image Located
Image Sent
Image
retrieval
service
Backup
Storage
Located in
another
geographical
location
Think about options to deal with extra
large data sets

27. Image
Write
Service
Storage
Upload Image
Files written
to storage
Request Image
Client Computer
Image Located
Image Sent
Image
retrieval
service
Backup
Storage
Located in
another
geographical
location
horizontal and vertical scaling
Horizontal
Vertical
Adds more storage /
processing power etc. to the
same server
Adds more nodes/shards (this
is the preferred option for big web
services)

28. Image Write
Service
Storage
Upload Image Files written
to storage
Request Image
Client Computer
Image Located
Image Sent
Image
retrieval
service
Backup
Storage
Located in
another
geographical
location
Image Write
Service
Storage
Backup
Storage
Image
retrieval
service

29. Image Write
Service
Storage
Upload Image Files written
to storage
Request Image
Client Computer
Image Located
Image Sent
Image
retrieval
service
Backup
Storage
Located in
another
geographical
location
Image Write
Service
Storage
Backup
Storage
Image
retrieval
service

30. Services
Separate key web services into different
logic nodes
Redundancy
Make sure that there is backup of all
data
Partitions
Split everything into different partitions/
shards to deal with increasing data
usage

31. Presentation
Logic
Business Logic Database
we can go from this…

32. Presentation
Logic
Business Logic
Business Logic
Database
Database
Database
Database
Database
Database
Database
Database
…to this

33. scaling services up for use
in an enterprise level web
program

34. 4 methods that we are
going to look at:
Caching
Proxies
Load Balancing
Queuing

35. scaling services up for use
in an enterprise level web
program
Caches

36. Application
Server
Database
server
I would like an image of a dog

37. Application
Server
Database
server
I would like an image of a dog
too many images to physically sort through

38. Application
Server Database
server
I would like an image of a dog
• Use a cache to store things that are sorted for most
recently
• There’s a good chance that if something is searched
for once, it is going to be searched for again
cache
Cache is checked before
going to the DB server

39. Application
Server Database
server
I would like an image of a dog
• This tiny change makes a big difference to application
speed!
• Cache reads are lightning fast
• Database server reads are snails pace in comparison
cache
Cache is checked before
going to the DB server

40. Database
server
Application
Server
cache
Application
Server
cache
Application
Server
cache
Application
Server
cache
I would like an image of a dog
Doesn’t always work as
expected. Doing things this
way can create a cache miss
Distributed cache system

41. Database
server
Application
Server
cache
I would like an
image of a
dog
Each request that is made passes through a
cache, if it has the data it returns it, if not it goes to
the database
Global cache system I
Application
Server
Application
Server
Application
Server
This is the most common type of cache system

42. Database
server
Application
Server
cache
I would like an
image of a
dog
Application server checks the cache, if it doesn't
find what it is after the application server then
goes to the database
Global cache system II
Application
Server
Application
Server
Application
Server
Better for large files that may otherwise clog the
cache. Also better for static cache files

43. Want to give it a go?
http://memcached.org/
http://www.phpfastcache.com/
(documentation is online)
Caches

44. scaling services up for use
in an enterprise level web
program
proxies

45. Database
server
I would like
an image of a
cat
Application
Server
Proxy

46. Database
server
I would like
an image of a
cat
I would like
an image of a
cat
I would like
an image of a
cat
I would like
an image of a
cat
Application
Server
Application
Server
Application
Server
Application
Server
Proxy
Proxies are good
when lots of people
are searching for
the same thing
Collapses requests
into a single
request, reduces
database reads
Bring me the
cats!

47. Database
server
I would like
an image of a
black cat
I would like
an image of a
ginger cat
I would like
an image of a
tabby cat
I would like
an image of a
fluffy cat
Application
Server
Application
Server
Application
Server
Application
Server
Proxy
Also good if people
are searching for
close to the same
thing
Bring me the
cats!

48. Database
server
I would like
an image of a
black cat
I would like
an image of a
ginger cat
I would like
an image of a
tabby cat
I would like
an image of a
fluffy cat
Application
Server
Application
Server
Application
Server
Application
Server
Proxycache
We can use techniques at
the same time to make it
even faster.
A lot of proxies actually
come with a cache built into
them

49. Want to give it a go?
http://www.squid-cache.org/
https://www.varnish-cache.org/
(documentation is online)
proxy/cache

50. scaling services up for use
in an enterprise level web
program
load
balancing

51. Database
server
I would like
an image of a
black cat
I would like
an image of a
ginger cat
I would like
an image of a
tabby cat
I would like
an image of a
fluffy cat
Application
Server
Application
Server
Application
Server
Application
Server
Magic Box
!?!?
!?!?

52. I would like
an image of a
black cat
upload a
picture of a
ginger cat
I want to
change my
password
I just really
like cats
Application
Server
Application
Server
Application
Server
Application
Server
Load
Balancer

53. I would like
an image of a
black cat
upload a
picture of a
ginger cat
I want to
change my
password
I just really
like cats
Application
Server
Application
Server
Application
Server
Application
Server
Load
Balancer
Load
Balancer B

54. I would like
an image of a
black cat
upload a
picture of a
ginger cat
I want to
change my
password
I just really
like cats
Application
Server
Application
Server
Application
Server
Application
Server
Load
Balancer
Load balancing methods
round robin
Random node
As it sounds…just picks a random node
Node with most free processing power
Node with access to [x]
Criteria based
Location based
node[x], node[x+1], node[x+2]
Node in Aberdeen
Node in Dundee

55. Problems with load balancing
Managing user session data
You don’t want to be put to a different server node
every time you change a page
Even changing a node every time you visit a site
would be a pain! (shopping basket might be
deleted)

56. Want to give it a go?
http://www.haproxy.org/
(documentation is online)
load balancing

57. scaling services up for use
in an enterprise level web
program
queues

58. Database
server
Application
Server
Application
Server
Application
Server
Application
Server
Sends
write
Waits for
response
Sends
write
Sends
write
Sends
write
Waits for
response
Waits for
response
Waits for
response

59. this is torture

60. Queues are good for writing data
caches, proxies and load balancing are all
good for reading data

61. Database
server
Application
Server
Application
Server
Application
Server
Application
Server
Sends
write
Sends
write
Sends
write
Sends
write
queue
writing to the queue gets
instant acknowledgment
Sends writes
when
database is
available

62. Want to give it a go?
http://zookeeper.apache.org/
http://www.rabbitmq.com/
(documentation is online)
queues

63. Recap
•Tier architecture and cloud computing
•Moving from 3-tier to n-tier
•Scaling services up for use in Enterprise web
•Caches
•Proxies
•Load Balancing
•Queueing