Here is an excellent slide on Exchange 2013 Storage, High Availability and Site Resilience.
Some of the key features are as follows.
Passive copy DB on 2013 consumes 50% of the iops of the iops required for an active copy.
Autoreseed – Can use spare disks. Periodically scan for failed and suspended copies, check pre-requisites,allocate remap a spare, start the seed, verify health, alert admin about failed disk.
Data Center Failover can be automated.
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