Ext3 users - Nov 2006 - ext3 4TB fs limit on amd64 (FAQ?)

Hi,

I've a question about the max. ext3 FS size. The ext3 FAQ explains that
the limit is 4TB.

http://batleth.sapienti-sat.org/projects/FAQs/ext3-faq.html

| Ext3 can support files up to 1TB. With a 2.4 kernel the filesystem size
is | limited by the maximal block device size, which is 2TB. In 2.6 the
maximum | (32-bit CPU) limit is of block devices is 16TB, but ext3
supports only up | to 4TB.

Other sources claim that the limit is 8TB (RedHat ES). I'm using ubuntu
dapper drake 6.06 with kernel 2.6.15. At the momente I'm running the amd64
port. I successfully created the ext3 FS on a 4,5TB lvm partition
(standard ext3 fs options) and was able to fill the whole fs with data.
Afterwards I checked the data with md5sum and did a fsck, everything seems
to be fine so far.

Was it just luck that I didn't see any data corruption? Can I use ext3 for
fs >4TB<8TB on amd64 these days? I also tried xfs, but unlike ext3 it
repeatable froze the system when I ran the tiobench benchmark.

Ralf

On Sun, 26 Nov 2006, Ralf Gross wrote:
> I've a question about the max. ext3 FS size. The ext3 FAQ explains that
> the limit is 4TB.
Hm, strange: I'm pretty sure that mkfs.ext3 understands bigger 
blocksizes for quite a while now. Then again, the FAQ says 
"Version: 2004-10-14"...

So, although I'd really love to have this information (and the FAQ!) on
http://e2fsprogs.sf.net/  this is what I found:

blocksize	file size limit 	filesystem size limit
  1 KiB		16448 MiB (~ 16 GiB)	2048 GiB (= 2 TiB)
  2 KiB	 	256 GiB 		8192 GiB (= 8 TiB)
  4 KiB		2048 GiB (= 2 TiB) 	16384 GiB (= 16 TiB)
  8 KiB	 	65568 GiB (~ 64 TiB) 	32768 GiB (= 32 TiB)

Note that an 8 KiB blocksize is only supported on systems with 8 KiB 
pagesize (i.e. linux/alpha).

So, it really looks like 16TiB shouldn't be a problem...but I just 
stumbled over this:
https://www.redhat.com/archives/ext3-users/2006-October/msg00000.html

While the ext* gurus are busy on the ext4 list, I too would appreciate 
a comment on the current limitation of ext2/ext3/ext4, so that we can 
update the FAQ. These questions really come up way too often...

Thanks,
Christian.
-- 
BOFH excuse #387:

Your computer's union contract is set to expire at midnight.