Review the following considerations before tuning ZFS:
Default values are generally the best value. If a better value exists, it should be the default. While alternative values might help a given workload, it could quite possibly degrade some other aspects of performance. Occasionally, catastrophically so.
The ZFS best practices should be followed before ZFS tuning is applied. These practices are a set of recommendations that have been shown to work in different environments and are expected to keep working in the foreseeable future. So, before turning to tuning, make sure you've read and understood the best practices. For more information, see Chapter 12, Recommended Oracle Solaris ZFS Practices in Managing ZFS File Systems in Oracle Solaris 11.4.
Unless noted otherwise, the tunable parameters are global and impact ZFS behavior across the system.