Re: Heads up

On Fri, Apr 15, 2016 at 11:49 AM, olli hauer <ohauer_at_gmx.de> wrote:

> On 2016-04-15 06:19, Warner Losh wrote:
> > On Thu, Apr 14, 2016 at 9:56 PM, Warren Block <wblock_at_wonkity.com>
> wrote:
> >
> >> On Thu, 14 Apr 2016, Warner Losh wrote:
> >>
> >> The CAM I/O scheduler has been committed to current. This work is
> described
> >>> in https://people.freebsd.org/~imp/bsdcan2015/iosched-v3.pdf though
> the
> >>> default scheduler doesn't change the default (old) behavior.
> >>>
> >>> One possible issue, however, is that it also enables NCQ Trims on ada
> >>> SSDs.
> >>> There are a few rogue drives that claim support for this feature, but
> >>> actually implement data corrupt instead of queued trims. The list of
> known
> >>> rogues is believed to be complete, but some caution is in order.
> >>
> >>
> >
> >> Is the list of drives queryable?  Is there an easy way to tell if the
> >> currently-connected drives are on the list?
> >>
> >
> > /usr/src/sys/cam/ata/ata_da.c has the list.
> >
> > dmesg will tell you if it detected a bad one since it prints the drive's
> > quirks.
> > But that's no big deal, because the bad one work just fine if you never
> > issue
> > a NCQ TRIM. This small group of drives were early adapters of this
> > technology
> >
> > Here's the full list of known rogues:
> >
> > Crucial/Micron M500 (all firmware prior to MU07)
> > Micron M510 MU01 firmware (newer firmware is good)
> > Crucial/Micron M550 MU01 firmware (newer firmware is good)
> > Crucial MX100 MU01 firmware (newer firmware is good)
> > FCCT M500 all firmware
> > Samsung 830 all firmware
> > Samsung 840 all firmware
> > Samsung 850 all firmware
> >
> > All of these are at least 18 months old (if not older). There's some
> > confusing in Linux lists on
> > the full impact of the Samsung drives (there was a bug in the Linux
> > implementation (that can't
> > be present in the FreeBSD implementation) that may have been the root
> cause
> > for the Samsung
> > black listing). Out of an abundance of caution, I've kept them in the
> list.
> > Also, it's my belief that
> > the Crucial/Micron models with MU01 firmware were mostly corrected after
> > early samples
> > since most of the channel drives I've helped people debug had MU02
> > firmware. Also, a quick
> > google search shows the MU02 firmware for each of these models has been
> > available for
> > at least a year.
> >
> > Warner
>
> I suspect this was the reason why Samsung SSD's are listed on the Linux
> blacklist.
> https://blog.algolia.com/when-solid-state-drives-are-not-that-solid/
>
> But the article also reports it was a Linux kernel issue ..
>

I've done a lot of research for this issue. There's two reasons they were
listed. One was a Linux kernel bug. The other was that early drives reported
that it was supported when, in fact, it wasn't. I've constrained the list to
the latter.

Warner