Exchange DR planning ? realizing the importance of backing up the Directory

Introduction
Exchange relies on Active Directory (AD) as its enterprise directory, storing configuration, user and routing data. Therefore, it is imperative that Exchange specific data be secured at the directory level. This Article will explore a number of factors to consider, when securing your directory from disaster.

Active Directory Partitions & its Data?
Most of us have experiences some kind of downtime, mostly however from storage outages. The other side of the coin is, what do we do if AD breaks, or there's a large "oops" and mail attributes are lost for one or many users?

In this article we?re going to expel the factors and some solutions around backing up and recovering Exchange configuration data quickly.

Exchange specific data is stored in three AD partitions:

Domain Partition:

Hosts users and the mail attributes

Configuration Partition:

Hosts Exchange specific configuration data

Schema partition:

Hosts the definition of mail attributes

 

 

 

All three partitions are normally backed up as part of a Domain Controller backup, however when we?re talking about quick recovery, backing up once a night isn't the only factor to consider. A number of other factors may come into play, including:

?        Number of domains
 

?        Number of sites

?        Link speed and latency

?        Frequency of AD updates

?        User/object Churn

?        Exchange deployment in a multi domain forest

?        Other applications hosting their data in AD

?        MIIS or ADAM

Disaster Recovery Planning
Disaster recovery or the definition thereof is highly subjective to each organization; here are a few scenarios that might affect you:

?        Total outage/total loss,

?        Partial outage/loss (attribute loss is a good one),

?        Stolen/failed hardware

?        Loss of physical site/building

Also, in defining an SLA (Service Level Agreement) to the business, what are your guaranteed timescales to recovery?

These factors will help dictate where/how and how often you want to backup, including how many backup methods you employ.

Things to mention here is that a backup is not a backup unless you can restore it, this means if you're using tape, then test the tape. At least you can see if what on the tape will make sense.

Depending on your Forest design, having at least one lag site, i.e. a separate site containing at least one Domain Controller (DC) that is a few hours up to 24 hours behind the rest of the forest in terms of replication schedule.