mpt(4) cuts 3TiB drives down to 2TiB

[Kenneth D. Merry]

On Sun, May 08, 2011 at 12:31:28 -0700, Artem Belevich wrote:
> On Sun, May 8, 2011 at 5:13 AM, Michael Reifenberger
> <mike at reifenberger.com> wrote:
> > Hi,
> > the manpage of mptutil states that mpt(4) doesn't support volumes greater
> > 2TiB,
> > it suggests to use the disks in JBOD mode.
> >
> > Even this seems only to work for disk with less than 2TiB.
> >
> > When attaching a Hitachi 7k3000 drive on the LSI SAS/SATA ports of a
> > Supermicro X8ST3-F board I only see 4294967294 sectors while I get 976773168
> > sectors when
> > attaching to the on board SATA ports.
> >
> > This leaves the onboard LSI controller useless for bigger disks.
> >
> > Is there a way to work around this issue?
> >
> > Or is anybody working on enhancing the mpt(4) driver to use the newer API?
> 
> According to LSI, it's a 'feature'.  Controllers based on
> LSI1068/1068e (X8ST3-F  uses LSI 1068E)  truncate drive capacity to
> 2TB:
> http://kb.lsi.com/KnowledgebaseArticle16399.aspx

I have heard from a friend (i.e. I haven't personally confirmed) that the
capacity truncation only applies to SATA drives.  If you attach a 3TB SAS
drive, you should be able to see the full capacity.

It makes some sense, since the LSI controller is translating SCSI to SATA,
but for SAS drives it just passes the SCSI commands straight through to the
drive.  So the 16 byte READ CAPACITY, READ and WRITE commands will make it
through to SAS disks, but aren't translated for SATA disks.

Ken
-- 
Kenneth Merry
ken at FreeBSD.ORG