Device's "stolen" sector

[Domagoj Smolčić]

On Tue, 16 Jul 2019 13:27:43 -0600
Warner Losh <imp at bsdimp.com> wrote:

> On Tue, Jul 16, 2019 at 11:05 AM Wojciech Puchar <wojtek at puchar.net>
> wrote:
> 
> >
> >
> > On Tue, 16 Jul 2019, Domagoj Smolčić wrote:
> >  
> > > 11.2-RELEASE-p9
> > >
> > > Tested with >1 disks:
> > > --
> > > SATA disk connected directly with SATA cable to MBO, shows
> > > correct  
> > amount of sectors.  
> > >    diskinfo -v ada1
> > >
> > > When I connect it to the same MBO over USB to SATA adapter, 1
> > > sector is  
> > missing (the last one)  
> > >    diskinfo -v da0
> > >
> > > Having last sector inaccessible is a huge problem as many
> > > "things" use  
> > it for a metadata.  
> > > This has many times caused MBR disks occasionally to not be
> > > visible at  
> > all while being 'da0' (gpart: No such geom: da0.)  
> > > And also GPT disks to be in a [CORRUPT] state upon reattach
> > > directly to  
> > SATA interface.  
> > >
> > > Before submitting a bug, there is only 1 variable left that I
> > > can't  
> > test, because I have only 1 USB to SATA adapter.  
> > > It might be a hardware issue, so can someone else test this too?
> > >  
> > i have two external disk chassis with USB-SATA bridge, works just
> > fine
> >
> > recently connected through it disk that was geli encrypted when
> > directly connected to server. geli worked so all is fine as geli
> > header is in last sector
> >  
> 
> It all depends... There's huge variation in the quality of USB-SATA
> bridges. Some get in the way and do things like round off the last
> sector when the reported capacity is odd, for example. Which is why
> I'm trying to see if there's an issue with that, or if the issue is
> something in the da driver. For drives with an even number of
> sectors, there's likely no issues at all...
> 
> Warner
> 

Well, I've installed sysutils/sg3_utils, but required sg device will have to wait,
as I can't recompile kernel ATM.

Regarding quality ..., this one was so cheap that I've got it for free. ;)
Regarding capacity ..., HDD has EVEN number of sectors.

Last HDD checked (just before posting) Hitachi:
========
# diskinfo -v ada1 | awk '/mediasize in sectors/{print $1}'
312581808

# gpart show -p ada1
=>       63  312581745    ada1  MBR  (149G)
    312581745 + 63 = 312581808

All OK!


# diskinfo -v da0 | awk '/mediasize in sectors/{print $1}'
312581807

# gpart show -p da0
gpart: No such geom: da0.
    Showed nothing (usually it does even in this cases)


Domagoj Smolčić