The FreeBSD wiki (https://wiki.freebsd.org/ZFSTuningGuide) still claims:
> To use ZFS, at least 1 GB of memory is recommended (for all architectures) but more is helpful as ZFS needs lots of memory.
Is that inaccurate?
> To use ZFS, at least 1 GB of memory is recommended (for all architectures) but more is helpful as ZFS needs lots of memory.
Is that inaccurate?
There are two additional things to consider.
ZFS uses RAM mostly for aggressive caching to cover over both spinning disks and the iops tradeoff vdevs make over traditional raid arrays. Thus low memory is not such a big deal if you have a pool with a single SSD or NVMe device.
The other point to consider is that on at least any non-Solaris derived platforms, the VFS layer does not speak ARC. So data is copied from an ARC object into a VFS object, taking up space in both. If you are able to adopt your platform to use the ARC as direct VFS cache, you can save RAM that way as well.
As for the recommended amount of system memory, recommended amounts are not the minimum amount which code requires to run. It in no way contradicts my point that the code itself does not need so much RAM to operate. However, it will perform better with more until your entire working set is in cache. At that point, more RAM offers no benefit. It is the same with any filesystem.