[lustre-discuss] Problems moving an OSS from an old Lustre installation to a new one

Mohr Jr, Richard Frank (Rick Mohr) rmohr at utk.edu
Tue Jul 28 07:13:49 PDT 2015

> On Jul 28, 2015, at 1:46 AM, Massimo Sgaravatto <massimo.sgaravatto at pd.infn.it> wrote:
> Indeed we forgot to shutdown the old MGS/MDS before "attaching" the old OSS to the new one, but I wonder why this caused problems.

If the old MDS contacted the old OSS, and the file system names were still the same between the new and old file systems, maybe the old OSS still processed some config file from the old OSS and this started causing issues.

> Our idea now would be to retry the mkfs operations (this time they would be done with the old MDS switched down)
> Do you see some better options ?

Before doing mkfs, I would try running a writeconf to recreate the config logs (making sure the old MDS is powered off).  That might clear out any old data and fix things.

In general, I would highly recommend not having two Lustre file systems up and running with the same file system name.  It is probably safer just to assign a new name to a new file system in case there are any conflicts (although you can still mount the Lustre file system at the same location).

Rick Mohr
Senior HPC System Administrator
National Institute for Computational Sciences

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