Subject: Re: File system > 1 Terabyte
To: Jason Thorpe <>
From: Ben Collver <>
List: current-users
Date: 09/30/2004 15:36:25
On Thu, Sep 30, 2004 at 02:53:37PM -0700, Jason Thorpe wrote:
> >Where does the 1TB limitation come from?
> FFS addresses everything by "fragment".  FFSv1 has a 32-bit signed 
> fragment number, meaning you're limited to 2^31 fragments.  FFSv2 has a 
> 64-bit signed fragment number.
> Arithmetic is left as an exercise for the reader.

If my arithmetic is exercised correctly, with a block size of 16k and a
fragment size of 2k (as recommended by the newfs man page for very large
filesystems), this would put the max filesystem size at 2^31*2048 bytes.
This is 4TB, but as you said it is capped by the disklabel at 2TB.

You said "You cannot create a file system larger than 1TB with the FFS
code in 1.6.2."
Message-Id: <>

Where does this 1TB limit come from?

-Lazy Ben