ZFS, SSD and encryption

[Eric A. Borisch]

On Friday, July 22, 2016, Karl Denninger <karl at denninger.net> wrote:

>
> On 7/22/2016 07:48, Nikos Kastanas wrote:
> > I have a Lenovo X220 laptop running FreeBSD 10.3-RELEASE with ZFS and
> > encryption on a plain HDD. I am considering buying a Samsung Pro 850 SSD
> to
> > boost performance but I am not sure if TRIM and ZFS+Encryption work well
> > together. After some research online, I found *this page*
> > <https://www.freebsd.org/doc/faq/all-about-zfs.html>which states the
> > following:
> >
> > *Note: *
> > ZFS TRIM may not work with all configurations, such as a ZFS filesystem
> on
> > a GELI-backed device.
> >
> > From what I can understand from the above note, I should not use the
> > encryption option when installing FreeBSD with ZFS on an SSD. TRIM will
> not
> > work correctly and therefore the SSD performace will be impacted.
> Meh.  Simply not true.
>

It will not work on 10.3, but will work (as Karl demonstrates) on
11.x. Here's the commit to head enabling it:

https://svnweb.freebsd.org/base?view=revision&revision=286444

And here's what is in 10.3 (BIO_DELETE case returns EOPNOTSUPP):

https://svnweb.freebsd.org/base/releng/10.3/sys/geom/eli/g_eli.c?revision=296373&view=markup#l319

 -  Eric