I believe there are 2 limits you may be encountering.  The disk is larger
than 2TiB and is low-level formatted with 4096 bytes sectors.  The 2TiB
limit results from clculations with 32 bit integers and 512 byte sectors.

The large sector size is almost certainly the problem with "dd"...you
can read less than a sector, but an attempt to write less than a sector
will fail.  Try bs=4k.

I'm running 8 Stable as of a few days ago.  The "fdisk" sources on
this system were updated 11/22/2010, but appear to handle sector sizes
up to 2048 bytes.  I haven't checked to see if it handles disk or
sizes above 2TiB, but it doesn't matter, it won't handle your disk
and I doubt that the FBSD 7.3 fdisk would either.  There is no option for
sector size, it's a hard-coded limit which is too small.

Bsdlabel may have similar limits.  The version on this system was last
modified 09/26/2010.  It reads the sectorsize from the disk and therefore
should have no trouble with a 3tb disk.  I don't know whether the 7.3
fdisk has these modifications, but with fdisk failing, it doesn't matter.
If you are using the disk only under freebsd you might try using
on the entire disk (da0), but check I suspect your bsdlabel may not be
upgraded yet (check sbin/bsdlabel).

The manual page for 'gpart' claims that it was introduced in 7.0, and I
would think it would be working reasonably by 7.3.  It should be able
to handle large disks and partitions with no trouble, and is much easier
to use than the old stuff.  You said in your last email that 'gpart show'
showed nothing, but that may be because it had nothing intelligible to
show.  If you haven't tried it yet, and the disk contains no data which
you might lose, then try the recipe from the link I gave you.  Create
a couple of partitions, then try 'gpart show'.

Alternately, you may try getting recent versions of fdisk and bsdlabel
from cvs or svn, increase the sector size limit in fdisk, and try that
route again.

Duane H. Hesser

Thank you all for your input.  We must admit, we have a bit more reading
to do to fully understand what "Nagilum" was providing.  On the other
hand, we do understand more of what Mr. Hesser was saying, however, we
aren't prepared to upgrade to to 8.x or start playing around by
replacing/updating individual utilities on this 'live 7.3 system'.
Perhaps on a test machine 'first'.  Until then we will have to take the
whimp way out and format the 3TB USB device with NTFS and mount it until
we are better versed on exactly where Freebsds' support is for these HDD's
that are greater than @-TB in size.

We really would like at least one (1) FreeBSD machine that is all,
dedicated so to speak, BSD.

We will read that recipe.  Should anyone make additions to this thread we
are all eyes_&_ears.

As was mentioned before, the limitationcomes from the defintion of the partition structures. Firstly the fdisk structure introduced with the IBM PC (I think) has onlt room for 32 bits on its sector tables. secondly the bsd 'label' structure introduced
in the 80s has a similar limitiation.
The new structure to get around this is the GPT structure. you need to partition the drive with a gpt capable partitioning tool.. gpart claims to do this (though I have never done it as I don't have a need (yet)). This limitiation will affect any system which you wil use to write those partition types and is indepenent of file system. In addition Once you have made a partition big enough, you will need to populate it wirth a filesystem capable of representing data to that scale.
UFS2 and ZFS are two candidates for this.

If you take a modern Windows, it will probably partitionthe drive using a GPT table or some similar modern structure.(I don't have any modern windows system so I can't tell you exactly what they do, but they MUST have done the same thingif they didn't use GPT itself.) This is a separate step from puting the file system on, though the windows tools may
present it as a single step.

I hope y'all will find this useful.

freebsd-usb@freebsd.org mailing list
To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"

freebsd-usb@freebsd.org mailing list
To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"

Reply via email to