- Server Failure Add mailbox servers to a DAG and replicate databases to other servers in the DAG
- Disk Failure Place the edb file and log files on the same disk and ensure the database is replicated to at least three DAG members
- Database Corruption If a database goes bad you can set the ReplayLagTime so that copies of the database do not incorporate any dodgy transaction logs that caused the corruption on the active master. See this post.
- Single Message Recovery This is an important consideration but easy to solve. Exchange now has single item recovery built in. You need to enable it and specify how long you want to keep deleted items for.
- Mailbox Recovery Deleted mailboxes are maintained for 30 days by default which can be configured to be longer if required
- Site Failure You should stretch your DAG to include subnets in different sites.
To enable circular logging of your log files, type in the following:
[PS] Set-MailboxDatabase DB01 -CircularLoggingEnabled $True