Date: Tue, 15 Feb 2000 09:50:13 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Joe Greco <jgreco@ns.sol.net> Cc: peter@netplex.com.au (Peter Wemm), hackers@FreeBSD.ORG Subject: Re: Filesystem size limit? Message-ID: <200002151750.JAA44270@apollo.backplane.com> References: <200002151608.KAA54469@aurora.sol.net>
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:> ie: there is a signed 32 bit sector count limit. 2^31 == 1TB. It shouldn't
:> be too hard to get it to create 2^32 bit (2TB) filesystem though. I'd expect
:> there to be more problems that this to bite you though. :-(
:>
:> 2^31 also happens to be the mmap() file offset limit FWIW.
2^31 blocks is the limit, because the filesystem uses negative block
numbers internally to represent metadata.
Theoretically you can use a larger block size and a larger sector size
and thus get more blocks, but unfortunately the kernel's device interface
translates everything to 512-byte blocks. It is not an insurmountable
problem, though, I can definitely see us supporting 2^31 x large_block
filesystems in the future. E.G. where a 64K block size would yield
a 128TB max fs size.
-Matt
Matthew Dillon
<dillon@backplane.com>
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