Re: >31 bit filesystems

Stephen C. Tweedie (sct@dcs.ed.ac.uk)
Sat, 3 Aug 1996 12:40:29 +0100


Hi,

On Fri, 2 Aug 1996 01:40:38 +0200, Andries.Brouwer@cwi.nl said:

> Mark Lehrer:
> : I am interested in making a large local ext2fs filesystem
> : of at the very least 4 gigs.

> : does linux' filesystem handle this? what is the
> : theoretical limit?

> Per file: 2 GB minus 1 block.
> Per filesystem: opinions differ, but 2 TB is an upper bound,
> (and I think 1 TB is possible).

Ext2fs limits are 2TB for 1k block filesystems (4TB and 8TB for 2k or
4k filesystems). Linux has a separate internal limit of 1TB for any
block device due to its addressing of block devices in units of
512-byte sectors.

The practical limit is therefore 1TB for ext2fs on linux/intel.
Larger filesystems ought to be possible on linux/axp, but that would
require a (user-transparent) recode of some internals to be 64-bit
clean.

Either way, you are unlikely to find that ext2fs is the limiting
factor (your hardware will run out first, for this year at least...).

The main problem is that ext2fs limits you to 2GB per file. Work is
in progress to allow larger files.

Cheers,
Stephen.

--
Stephen Tweedie <sct@dcs.ed.ac.uk>
Department of Computer Science, Edinburgh University, Scotland.