Messaging plays a crucial role in the day to day operations of most businesses. Millions of emails are sent around the world every second containing customer orders, confidential data and information critical to its recipients. But what happens when your email system goes down? Waterstons’ messaging specialists, Andrew Quinn and Nigel Robson, discuss the importance of a bulletproof messaging service to support your organisation’s communications. How do we protect ourselves against different types of failures, and how can we continue to provide effective services in a worst case scenario?

1. Messaging: Zero Downtime
Communications
Andrew Quinn & Nigel Robson
11/10/2013

2. Email and your Business
• Primary method of business
communications
• Stores critical business data
• Outages can result in financial loss
• Often don’t realise importance until it’s
gone

4. Some Definitions
• High Availability (HA)
– Preventing a service outage in the event of a
hardware or software failure
• Disaster Recovery (DR)
– Restoring services following a major outage
• Site Resilience
– Quickly recovering from the loss of a site (can be
HA or DR)
• Service Continuity
– Providing basic services during an outage

5. High Availability
Service Continuity
Disaster Recovery Site Resilience
!

6. High Availability
• Eliminate single points of failure
• Automatic recovery in the event of a failure
• Little or no loss of service

7. Single Points of Failure

8. High Availability Options
•
•
•
•
Clustering
Replication
Network Load Balancing
DNS Round Robin

9. Disaster Recovery
• Outage has occurred
• Restore services as quickly as possible
• Human intervention required

10. Disaster Recovery Options
• Backups
– Traditional / Virtual Machine
– Tape / Disk
• Replication
– Application level
– Storage level
– Virtual Machine level

11. Disaster Recovery Metrics
• Recovery Point Objective
– How much data loss will be incurred in the
worst case?
• Recovery Time Objective
– How long will it take to recover services in the
worst case?

12. Disaster Recovery Considerations
• Data consistency
– Application consistency
– Crash consistency
– Additional recovery steps
• Rehearsals
– Make sure it works!
• Access
– How will people access the recovered
services?

13. Evolution of Exchange
Recoverability: 2003
• Multiple servers using shared
storage
• Automatic recovery from
server failure
• No protection against storage
failure
• No offsite recovery

14. Evolution of Exchange
Recoverability: 2007
• More servers required
• No shared storage
• Automatic recovery from
server or storage failure
• Offsite replication to a
standby server
• Offsite recovery takes quite a
bit of manual work

15. Evolution of Exchange
Recoverability: 2010
• Less servers required (if
using load balancers)
• Automatic recovery from
server or storage failure
• Offsite replication to a live
server
• Offsite recovery time
significantly reduced

16. Evolution of Exchange
Recoverability: 2013
• Load balancers optional
• Automatic recovery from
server or storage failure
• Offsite replication to a live
server
• High availability across sites

17. Evolution of Exchange
Recoverability: Summary
Version
Protection
from Server
Failure
Protection
Offsite
from Storage Disaster
Failure
Recovery
Cross-Site
High
Availability
2003
Yes
No
No
No
2007
Yes
Optional
Slow
No
2010
Yes
Yes
Quicker
No
2013
Yes
Yes
Quicker
Yes

18. Modern Site Resilience
Datacentre 1
Witness Site
Datacentre 2
Exchange 2013
Server
File Share
Witness
Exchange 2013
Server
Office Workers, Home Workers, Remote Workers

19. Service Continuity
• Maintain incoming / outgoing messaging
service in the event of a complete
messaging infrastructure failure
• Typically implemented using a hosted
partner
• Often an add-on to hosted messaging
hygiene solutions

20. Service Continuity
Continuity
Provider
Internet
Continuity
Mailbox
Message
Queue
Webmail
Outlook
Mail Server

21. Summary
• Email has become critical to business
operations
• Highly resilient services have become
affordable to SMEs
• You can mix and match options to provide
a level of resilience to suit your needs and
budget

22. Q&A
Coming up…
Messaging: Protecting your Data and your Reputation
1st November 2013
Messaging: Harnessing the Cloud
15th November 2013