[Lustre-discuss] targets start order in Lustre 2.4.3

Riccardo Murri riccardo.murri at uzh.ch
Fri May 23 07:58:20 PDT 2014


The online Lustre manual recommends that Lustre targets are started in
this order[1]: MGT, MDT, OSTs, clients.

[1]: http://build.whamcloud.com/job/lustre-manual/lastSuccessfulBuild/artifact/lustre_manual.xhtml#dbdoclet.50438194_24122

Now we are setting up an HA cluster with Pacemaker, and a strict
ordering directive ("order ... Mandatory: ostXX mdt mgt") results in a
complete restart of all targets if the MGT is migrated. In my
experience (with Lustre 1.8.5) this is most of the time unnecessary,
and Lustre can recover from a single target restart.  However, we have
recently switched to Lustre 2.4.3 and things might have changed.

So the question is: is this order strict (in Lustre 2.4.3), or can a
target be stopped and restarted on another node without affecting the
targets running on other nodes?

Thanks for any help!


Riccardo Murri

Grid Computing Competence Centre
University of Zurich
Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)
Tel: +41 44 635 4222
Fax: +41 44 635 6888

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