[CentOS] Re: mkfs.ext3 on a 9TB volume -- [Practices] Striping across intelligent RAID cards

Bryan J. Smith b.j.smith at ieee.org
Mon Sep 12 17:04:26 UTC 2005

Francois Caen <frcaen at gmail.com> wrote:
> Wow! Odd! RH says 8TB but ext3 FAQ says 4TB.

Any filesystem originally designed for 32-bit x86 is full of
signed 32-bit structures.  The 2^31 * 512 = 1.1TB (1TiB)
limit comes from those structures using a 512 sector size.

Ext3 has used a couple of different techniques to allow
larger and larger support.  Depending on the hardware, kernel
(especially 2.4), etc..., there can be limits at 1, 2, 4, 8
and 16TiB.

Which is why the "common denominator" is 1.1TB (1TiB).  It
was rather enfuriating in front of a client when I attempted
to mount one Ext3 volume

> >From my personal testing on CentOS 4.1, you can't go over
> 4TB without kludging.
> > I then did a software RAIDO across them, and finally:
> > 
> > mke2fs -b 4096 -j -m 0 -R stride=1024 -T largefile4
> /dev/md0
> Joshua, thanks for the reply on this.
> There's something kludgy about having to do softraid across
> 2
> partitions before formatting. It adds a layer of complexity
> and
> reduces reliability. Is that the trick RH recommended to go
> up to 8TB?
> -- 
> Francois Caen, RHCE, CCNA
> SpiderMaker, LLC
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