zfs_arc_max
Parameter
- Description
-
Determines the maximum size of the ZFS Adaptive Replacement Cache (ARC). However, see user_reserve_hint_pct ZFS Parameter.
See also zfs_arc_min Parameter.
- Data Type
-
Unsigned Integer (64-bit)
- Default
-
75% of memory on systems with less than 4 GB of memory
physmem
minus 1 GB on systems with greater than 4 GB of memory - Range
-
Default value of
zfs_arc_min
tophysmem
- Units
-
Bytes
- Dynamic?
-
No
- Validation
-
Yes, the range is validated.
- When to Change
-
If a future memory requirement is significantly large and well defined, you might consider reducing the value of this parameter to cap the ARC so that it does not compete with the memory requirement. For example, if you know that a future workload requires 20% of memory, it makes sense to cap the ARC such that it does not consume more than the remaining 80% of memory.
- Commitment Level
-
Unstable