The online Lustre manual recommends that Lustre targets are started in
this order: MGT, MDT, OSTs, clients.
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!
Grid Computing Competence Centre
University of Zurich
Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)
Tel: +41 44 635 4222
Fax: +41 44 635 6888