[lustre-discuss] Large directory Feature in lustre 2.5.3

[Chris Hunter]

Hi Kurt, this seems to be your month for lustre adventures :/

Best I can tell this message means you have a directory with ~16M 
entries. That is a hard limit in older versions of ext3-based lustre 
(http://ext2.sourceforge.net/2005-ols/paper-html/node3.html)

According to LU-1365 (https://jira.hpdd.intel.com/browse/LU-1365). If 
you have a MDT formatted under an older version of lustre (specifically 
used old version mkfs.lustre) you get this message because at the time 
of the LU ticket, the e2fs userspace tools (ie. fsck) could not handle 
LARGEDIR feature.

I think you can ignore this warning if you are willing to live with the 
directory 16M entry limit. I would _guess_ this is fixed in newer 
version of e2fsprogs. However there may not be a way to add LARGEDIR 
feature without re-formatting the MDT volume.

regards,
chris hunter

> Date: Thu, 28 Jan 2016 16:15:41 -0500 (EST)
> From: Kurt Strosahl<strosahl at jlab.org>
> To:lustre-discuss at lists.lustre.org
> Subject: [lustre-discuss] Large directory Feature in lustre 2.5.3
> Message-ID:<189341774.1403835.1454015741354.JavaMail.zimbra at jlab.org>
> Content-Type: text/plain; charset=utf-8
>
> Hello,
>
>     Recently this message appeard in the metadata system on our lustre 2.5.3 file system.  Is there a way to enable this feature in 2.5.3?
>
> Jan 28 10:53:56 scmds14a kernel: LDISKFS-fs warning (device dm-1): ldiskfs_dx_add_entry: Directory (ino: 111675137) index full, reach max htree level :2
> Jan 28 10:53:56 scmds14a kernel: LDISKFS-fs warning (device dm-1): ldiskfs_dx_add_entry: Large directory feature isnot enabled on this filesystem
>
> w/r,
> Kurt J. Strosahl
> System Administrator
> Scientific Computing Group, Thomas Jefferson National Accelerator Facility