OS:
The base operating system version for FreeNAS 11.1 is FreeBSD 11.1-STABLE,
which brings in many bug fixes, performance improvements, updated and
new drivers, and new features.

OpenZFS:
There have been many improvements to OpenZFS. Users should notice a
significant speed difference when listing a large number of snapshots or
when deleting multiple snapshots and large files.

The algorithm used for scrubs and resilvers has received many speed
improvements which will be most noticeable on fragmented pools.

Resilver Priority has been added to Storage. This provides the ability to
run resilvering at a higher priority at configurable times and days of the
week.

SNMP:
The SNMP MIB has many improvements, including the ability to send SNMP
traps for new alerts. 

Hardware Support:
The hardware watchdog has been reenabled for recent firmware versions of
AsrockRack C2750D4I. The BMC bug which required the watchdog to be
disabled is resolved with the 00.30.00 or newer BMC firmware version. 

Cloud:
Cloud Credentials has been added to System. This can be used to provide a
secure connection to a cloud services providers. Supported services
include Amazon S3, Backblaze B2, and Google Cloud Storage.

Cloud Sync has been added to Tasks and can be used to synchronize files or
directories to remote cloud storage providers. 

Alerts:
The Send Test Alert button has been added to Alert Services.

IPMI:
The Identify Light button has been added to make it easier to identify a
system in a rack by flashing its IPMI LED light.

Time Machine:
Support for per-backup OS X Time Machine quotas has been added.