What's the secret to Ext4 on >16TB?

Wed Apr 8 19:05:16 UTC 2009

Michael Peek wrote:
> Ugh.
> 
> Disgruntled with JFS and XFS, I went through a lot of trouble to get a 
> 2.6.28 kernel compiled and running, along with e2fsprogs 1.41.4, all so 
> I could format a large RAID (>16TB) with ext4 -- which, as I understand 
> it, can support filesystems on the order of EB's...
> 
> So I can't figure out why I'm seeing the following error:

Probably because mkfs.ext4 is still limited to 16 TB.  Per
http://ext4.wiki.kernel.org/index.php/Ext4_Howto#Creating_ext4_filesystems
, "current e2fsprogs currently still limits the filesystem size to 2^32
blocks (16T for a 4k block filesystem). Filesystems larger than 16T is
one of the very next high-priority features to complete for ext4. "
http://kernelnewbies.org/Ext4#head-4e13646f1961f41bf99152eaf137d309723ac524
also says 16 TB filesystems are not yet available.

Matt Flaschen