On Wednesday, 15 May 2002 at 18:27:30 +0200, Manuel Bouyer wrote:
> On Thu, May 16, 2002 at 01:11:33AM +0900, yutaka@mailhost.net wrote:
>>
>>
>> Manuel,
>>
>> Thank you for your mail.
>>
>> At Wed, 15 May 2002 10:39:44 +0200,
>> Manuel Bouyer wrote:
>>
>>> However, as already said, you can't have a filesystem larger than 1T,
>>> so you have to make your partition a bit smaller to make it work.
>>
>> Well, I thought I could make it if I did 'newfs -f 1024' not the
>> default size of 512k.
>>
>> My understanding was there are two alternate way to have 2TB BSD
>> pertition.
>>
>> 1. to set 1024byte / sector while writing disklabel.
>> This is OK for filesystem itself but OS supports 512byte/sector
>>
>> 2. to set -f 1024 when making filesystem (newfs)
>> This shold be OK but disklabel command does not understand such large
>> number.
>
> I think -f 1024 is already the default. This sets the fragment size,
> not the sector size. The problem (if I understood it properly) is
> that low-level filesystem operations use signed integers to
> represent sizes in sector size unit.

Most of the block I/O subsystem works with 32 bit signed sector
numbers.  In particular, IIRC, (small) negative values are used to
indicate error conditions.  We've tried this in FreeBSD, and we've
never got beyond 1 TB.  I suspect it's possible to get almost to 2 TB
(ignoring sector numbers which correspond to error numbers), but I
expect it would be quite a bit of work, and it would give rise to
compatibility issues.

Greg
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