[lustre-discuss] Target names changing when mounting

Mohr Jr, Richard Frank (Rick Mohr) rmohr at utk.edu
Fri Jul 31 12:09:15 PDT 2015

> On Jul 31, 2015, at 2:49 PM, Drokin, Oleg <oleg.drokin at intel.com> wrote:
> Well, using those symlinks was certainly not expected when this code was written.
> So I imagine avoid using them and perhaps use /dev/disk/by-uuid which should be more stable
> in the face of writeconfs

For sites using multipath, the by-label device won’t be used because (if I recall correctly) this can lead to some problems.  So in that case, this issue would not be seen.  For setups without multipath, using the by-label device can be incredibly convenient (and makes it a lot easier to tell which device corresponds to which OST).

But for me, the more confusing aspect was the discrepancy of the names in the tunefs output:

>>>  Read previous values:
>>> Target:     WORK2-MDT0000
>>>  Permanent disk data:
>>> Target:     WORK2:MDT0000

It looks like the Lustre code reads the label, and if it sees a “:” or “=“, it sets an appropriate flag.  But then it also modifies the string internally to replace “:” or “=“ with a “-“ character.  This modified string seems to get printed for the “previous value” section, but the original unmodified string gets printed for the “permanent value” section.  I think at the very least those strings should match.

Rick Mohr
Senior HPC System Administrator
National Institute for Computational Sciences

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