ext3 4TB fs limit on amd64 (FAQ?)

[Ralf Gross]

Christian Kujau said:
> 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

Thus with 4 KiB blocksize and a < 8TiB fs I should be on the safe side.

> 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...

Yes, the FAQ is a bit misleading.

ralf