[lustre-discuss] ldiskfs / mdt size limits

[Thomas Roth]

Hi all,

  confused  about size limits:

I distinctly remember trying to format a ~19 TB disk / LV for use as an MDT, with ldiskfs, and failing to do so: the max size for the underlying ext4 is 16 TB.
Knew that, had ignoed that, but not a problem back then - just adapted the logical volume's size.

Now I have a 24T disk, and neither mkfs.lustre nor Lustre itself have show any issues with it.
'df -h' does show the 24T, 'df -ih' shows the expected 4G of inodes.
I suppose this MDS has a lot of space for directories and stuff, or for DOM.
But why does it work in the first place? ldiskfs extends beyond all limits these days?

Regards,
Thomas

-- 
--------------------------------------------------------------------
Thomas Roth
Department: Informationstechnologie
Location: SB3 2.291


GSI Helmholtzzentrum für Schwerionenforschung GmbH
Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de

Commercial Register / Handelsregister: Amtsgericht Darmstadt, HRB 1528
Managing Directors / Geschäftsführung:
Professor Dr. Paolo Giubellino, Jörg Blaurock
Chairman of the Supervisory Board / Vorsitzender des GSI-Aufsichtsrats:
Ministerialdirigent Dr. Volkmar Dietz