On Thu, Jul 20, 2000 at 06:33:42PM +0930, Greg Lehey wrote:
> On Thursday, 20 July 2000 at 9:55:13 +0100, Geoff Buckingham wrote:
> A thing that might bite you here is that ufs is currently limited to 1
> TB per volume. Vinum doesn't have that restriction: if you want to
> create a 20 TB volume, and you know how to use the space, Vinum should
> work. The problem with ufs is that the block numbers in the inodes
> are 32 bit signed values. With 512 byte sectors, the only we can do
> it, that means a total address space of 2**9 * 2*31, or 1 TB. At some
> time I suspect we're going to need to fix that.
Block numbers in inodes are not physical blocks (named sectorsize in
UFS source) but logical which is equal to the size of an fragment and
thus defaults to 1k.
The problem is the driver and VM layer.
If vinum would simulate 2k "physical" blocksize it may go up to 4TB
if you set the fragment size to 4k. I don't know if any
middle calculation might harm or VM is missbehaving.
The point I never digged deeper here is because you already sugested
changing the driver layer to 64bit byte numbers which was accepted if
I remember right.
Some of the systems I've setup are near this Limit so I spend some time
to find out where the show stoppers are.
--
B.Walter COSMO-Project http://www.cosmo-project.de
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