Memory usage appears a bit high

Steve O'Hara-Smith steve at
Thu Jan 17 05:35:15 UTC 2019

On Wed, 16 Jan 2019 15:45:08 -0500
"James B. Byrne" <byrnejb at> wrote:

> As I have never meddled with the sysctl settings on this bhyve host I
> infer that this setting in sysctl is calculated based on the total
> memory allocated when the vm is created:
> vfs.zfs.arc_max: 3043799040

	Which is probably fine if the server isn't doing anything else that
demands much memory.

> How much should be committed to arc in a 4GB system?  What are the
> benefits / costs of more or less ram allocated to arc?

	The more RAM in the ARC the better the caching and therefore (with
a cache friendly workload) the faster the filesystem and the lower the rate
of wear on the drives. The downside - the ARC is wired so you need to
assess how much RAM the server needs for other tasks and throttle the ARC
to suit.

Steve O'Hara-Smith                          |   Directable Mirror Arrays
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