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What's the proper way on FreeBSD 9 to tune ZFS parameters such as vfs.zfs.arc_max and vfs.zfs.vdev.cache.size? I've seen references to /boot/loader.conf, /boot/kernel.conf and /etc/sysctl.conf but I have none of those files.

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  • /boot/loader.conf is optional file which can be created by user to modify defaults (/boot/defaults/loader.conf).
  • /etc/sysctl.conf is exists in /usr/src/etc, but it can be empty file also. it is not critical file too.
  • I don't see any mention about /boot/kernel.conf in FreeBSD sources and /boot directory.

so, you can do:

  • (echo 'vfs.zfs.arc_max="…"'; echo 'vfs.zfs.vdev.cache.size="…"')>> /boot/loader.conf (replace … with something useful) and reboot
  • place same lines without double quotes into sysctl.conf and restart/reload sysctl
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