Re: Set ZFS pool ashift=14 for FreeBSD root pools?

On Tue, 12 May 2026 at 20:54, Dag-Erling Smørgrav <[email protected]> wrote:
>
> Lionel Cons <[email protected]> writes:
> > Is there a way to autodetect VMware, and then use an ashift balue
> > which is double the block size of the parent root device? Because
> > setting the ashift to the block size of a VM disk, which uses the
> > block size of the parent FS, is a pretty bad idea.
>
> Why?

Because if the block size in both layers are the same, then prefetch
and other things tend to interact badly with each other. The "fix" is
to let the operating system IN the VM use a larger block size,
typically twice the size of the native block size of the underlying
layer/device.

Lionel