Re: periodic trim for ufs2 ssds

Warner Losh <imp_at_bsdimp.com> wrote on
Date: Fri, 08 Dec 2023 14:13:07 UTC :

> On Fri, Dec 8, 2023, 4:03 AM Olivier Certner <olivier.freebsd@free.fr>
> wrote:
> 
> > Hi,
> >
> > Did you consider trying 'fsck_ffs -B -E' on a toy system? From a glance
> > at the code, these flags are not exclusive and should do what you expect.
> >
> 
> 
> I wouldn't expect that to work...
> 
> If that works, then you also have the option of not turning on trim on the
> > FS and instead periodically doing it at once, like you can do on ZFS.
> >
> 
> I'd go the other way. I'd turn trim on for UFS and monitor the system under
> load. Newer drives I've evaluated have much better pathological behavior
> than the drives of a few years ago... there's a lot of left over fud about
> how it's always terrible...

Also, possibly try use of:

# sysctl -d vfs.ffs.dotrimcons
vfs.ffs.dotrimcons: enable BIO_DELETE / TRIM consolidation

possibly via loader.conf :

# grep trim /boot/loader.conf
vfs.ffs.dotrimcons=1

One can sometimes use:

# gstat -spod

for monitoring alternatives and get an idea if on-the-fly
trim is rate limiting activity compared to not having it
enabled.

===
Mark Millard
marklmi at yahoo.com