Accessing SCSI-Devices >2TB

[Xin LI]

Hi, Raphael,

On Wed, Jun 08, 2005 at 12:23:24PM +0200, Raphael H. Becker wrote:
> I tried to attach our new external RAID to my RENEG_5_4 box today using
> one logical drive of about 2326GB. 
> 
> The RAID was preconfigured with two 50% partitions which were assigned 
> to two LUNs. FreeBSD 5.4 was able to detect those as da1 and da2 with 
> full capacity. 
> 
> For particular reasons I need one filesystem.
> 
> The support for this RAID told me just SuSE Linux and W2k3/64Bit Systems
> are able to access devices >2TB (64bit LBA) therefore the larger RAIDs 
> are preconfigured with smaller partitions.
> 
> For me there will be 2+1 solutions to get this running,
> 
> a) (preferred): Having one logical drive w/o partitions or multiple LUNs
>    by doing some magic at my KERNCONF
> 
> b) reverting to 2 Partitions and doing ccd(4) on the resulting /dev/da(1|2)
> 
> ... maybe ... 
> 
> c) upgrading to a closer-to-current version to have some "hidden
>    feature" available?
> 
> Any other solutions?

Sure.  Actually even RELENG_5_3 has the support with a GENERIC kernel :-)

If you want a partition larger than 2TB, then you will want to use gpt(8)
instead of fdisk(8).  In order to use that, you need to have:

	options         GEOM_GPT

In your kernel configuration.

2TB is a hard limit for MBR partitions, but not GPT, as the latter is
designed for 64-bit operating system.  Fortunately this is also available
on FreeBSD/i386 (also amd64 as far as I have tested, and it is supposed
to be available on other platforms that FreeBSD supported).

Of course I think we should document this somewhere in our handbook,
and teach sysinstall(8) about it :-)

Cheers,
-- 
Xin LI <delphij frontfree net>	http://www.delphij.net/
See complete headers for GPG key and other information.

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