[lustre-discuss] Target names changing when mounting

Mohr Jr, Richard Frank (Rick Mohr) rmohr at utk.edu
Fri Jul 31 11:56:29 PDT 2015

> On Jul 31, 2015, at 2:08 PM, Andrus, Brian Contractor <bdandrus at nps.edu> wrote:

> I find this very confusing..
> I created a new lustre filesystem (WORK2) by creating and MDT and a single OST.
> When I first create them, the names shown for Target have different values from ‘Read precious values’ and ‘Permanent disk data’
> The difference is a hyphen ‘-‘ versus a colon ‘:’


> If I do a tunefs.lustre --writeconf , it changes the Permanent disk data AND the e2label to use an equal ‘=’ sign:

I too discovered this (the hard way) when I was trying to do some Lustre failover testing on our level system.

> Next time I mount it changes it back to the hyphen ‘-‘

As Oleg pointed out, that character is used to identify certain states for the OST, but as far as I can remember, I never saw that behavior documented anywhere.  It took us a couple hours to finally figure out what was happening.

> So.. What the heck???


> Now the problem/annoyance is the fact that this changes links in /dev…
> And an equal sign ‘=’ is NOT a happy character for device names…

Agreed.  We use the /dev/disk/by-label device names too, and in general this has never been an issue before.  We only noticed this odd behavior during our testing when a separate issue forced us to do multiple writeconfs and we started looking at the OST states.  IMHO, I would prefer it if this type of state information could be tracked elsewhere and not have the OST label change.  If nothing else, the current behavior should be documented.

Rick Mohr
Senior HPC System Administrator
National Institute for Computational Sciences

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