CNFS buffers bigger than 2 GB under Linux ?

Russ Allbery rra at
Mon Mar 18 19:09:41 UTC 2002

I'm not sure if it's the mailing list or your mail client, but all your
messages are arriving here in broken quoted-printable.

Antoine Delvaux <antoine.delvaux at> writes:

>> Well, you can just use large disk files.

> Yes, but this will slow down innd I think, no ?  That's why I wanted to
> use raw devices.

It may slow it down a bit, but we've not run bechmarks.  I doubt it will
be particularly noticeable.

> But does anybody knows where the 2GB limitation for rw devices comes
> from ?  INND or the Linux kernel ?

INN imposes no limitations; the limitation is in the kernel.  It's a
common limitation; I don't know of any operating system at present that
supports memory mapping raw devices over 2GB.  (Tru64, probably, if it
supports mmap on raw devices at all, but I'm not sure it does.)

Russ Allbery (rra at             <>

    Please send questions to the list rather than mailing me directly.
     <> explains why.

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