1. Cloud Computing Ed Lazowska August 2011 Bill & Melinda Gates Chair in
Computer Science & Engineering
University of Washington
August 2011

2. Personal computing Office applications Math and science Web browser
Databases and storage
9/9/2018 2

3. Cloud email accessed through the browser
Office applications
Math and science
Web browser
Databases and storage
9/9/2018 3

4. With the cloud provider’s domain name …

5. Or with your own …

7. Why not office applications too?
Math and science
Web browser
Databases and storage
9/9/2018 7

9. © 2009 Gribble, Lazowska, Levy, Zahorjan
Why not everything else?
Office applications
Math and science
Web browser
Databases and storage
9/9/2018
© 2009 Gribble, Lazowska, Levy, Zahorjan 9

11. Consider … Sharing is easy Someone else does backup
Someone else handles software updates
There’s 7x24x365 operations support, auxiliary power, redundant network connections, geographical diversity
Scalability – both up and down – is instantaneous
Many fewer demands on the local operating system and computer
Incredibly disruptive to existing business models!

12. Amazon Elastic Compute Cloud (EC2)
$0.68 per hour for
8 cores of 4 GHz 64-bit Intel Xeon or AMD Opteron
7 GB memory
1.69 TB scratch storage
Need it 24x7 for a year?
$3900
$0.085 per hour for
1 core of 1.2 GHz 32-bit Intel or AMD (1/20th the above)
1.7 GB memory
160 GB scratch storage
$490

13. 1000 processors for 1 day costs the same as 1 processor for 1000 days!
This includes
Purchase + replacement
Housing
Power
Operation
Reliability
Security
Instantaneous expansion and contraction
1000 processors for 1 day costs the same as 1 processor for 1000 days!

19. A datacenter has 50 - 250 containers
A container has 1, ,000 servers
A server has two processors, 2 disks, tons of memory, battery backup
Processors are chosen for power efficiency, not performance

20. Slide courtesy of Werner Vogels

21. Slide courtesy of Werner Vogels

22. Slide courtesy of Werner Vogels

23. Isn’t this just timesharing?
Many hundreds of machines are involved in a single Google search request (remember, the web is 400+TB)
There are multiple clusters (of thousands of computers each) all over the world
DNS routes your search to a nearby cluster

24. A cluster consists of Google Web Servers, Index Servers, Doc Servers, and various other servers (ads, spell checking, etc.)
These are cheap standalone computers, rack-mounted, connected by commodity networking gear

25. Within the cluster, load-balancing routes your search to a lightly-loaded Google Web Server (GWS), which will coordinate the search and response
The index is partitioned into “shards.” Each shard indexes a subset of the docs (web pages). Each shard is replicated, and can be searched by multiple computers – “index servers”
The GWS routes your search to one index server associated with each shard, through another load-balancer
When the dust has settled, the result is an ID for every doc satisfying your search, rank-ordered by relevance

26. The docs, too, are partitioned into “shards” – the partitioning is a hash on the doc ID. Each shard contains the full text of a subset of the docs. Each shard can be searched by multiple computers – “doc servers”
The GWS sends appropriate doc IDs to one doc server associated with each relevant shard
When the dust has settled, the result is a URL, a title, and a summary for every relevant doc

27. Meanwhile, the ad server has done its thing, the spell checker has done its thing, etc.
The GWS builds an HTTP response to your search and ships it off
Many hundreds of computers have enabled you to search 400+TB of web in ~100 ms.

28. Enormous volumes of data Extreme parallelism
The cheapest imaginable components
Failures occur all the time
You couldn’t afford to prevent this in hardware
Software makes it
Fault-Tolerant
Highly Available
Recoverable
Consistent
Scalable
Predictable
Secure