[Lustre-discuss] odd file entries

[Andreas Dilger]

On Jul 24, 2009  15:29 -0700, John White wrote:
> So we have a new file system set up.  beefy OSTs, but certainly under- 
> sized metadata (we're still figuring out what we'll use in the end).   
> We've just started to do friendly-user testing and ran into some odd  
> file entries.  In particular:
> -rw-r--r-- 1 ybao esd 22317940 Jul 23 10:49  
> met_em.d01.2060-12-30_12:00:00.nc
> ?--------- ? ?    ?          ?            ? met_em.d01.2060-F9?q
> -rw-r--r-- 1 ybao esd 22317940 Jul 23 14:30  
> met_em.d01.2061-01-01_18:00:00.nc
> 
> This seems to not only be an odd file entry, but might be messing with  
> proper wildcard listings.  For instance:
> [root at n0000 GFDLMET1]# ls met_em.d01.2060-01-01*
> ls: met_em.d01.2060-01-01*: No such file or directory

This generally means that the MDS has the directory entry for a file,
but the object is missing from the OST.  You will likely also have
"-2" (-ENOENT) errors on one of your OSTs.

In some cases, if a file is being deleted under load and the MDS
crashes the OST objects will still be deleted.  It isn't really
"data loss" because the file was being deleted, but it can be
confusing to users.

The simple solution is to use the "unlink" command to delete the
file (GNU "rm" will try to stat it first, and fail).

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.