Memory utilization
From OpenZFS on OS X
Memory Utilization
To set a persistent arc maximum, you need to create a new file /etc/zfs/zsysctl.conf. An example file is installed at /etc/zfs/zsysctl.conf.example.
Open /etc/zfs/zsysctl.conf in your favorite text editor, and add a line like this:
kstat.zfs.darwin.tunable.zfs_arc_max=11811160064
This would limit the arc max to 11GB (see table below).
You may also wish to set the arc meta limit explicitly. The default is 1/4 of the arc max, but for some workloads 3/4 may be more appropriate. Setting 3/4 of the arc max above:
kstat.zfs.darwin.tunable.zfs_arc_meta_limit=8858370048
For additional information, please see Performance.
