[LUDOC-268] Insert example MDS format cmd into Manual for multiple/failover nid - case

• Status: Open
• Project: Lustre Documentation
• Type: Improvement
• Priority: Minor
• Reporter: Thomas Roth
• Assignee: Lustre Manual Triage
• Resolution: Unresolved

Description

As of 2015-02-19, the Lustre 2.x manual lacks an explicti example of how to format MGS and MDT in case of

• separate MGS and MDT and
• failover pair of MDS where these two targets might be running

The proposed example is
"mkfs.lustre --mgs --servicenode=mgsNID1 --servicenode=mgsNID2 /dev/mgs-disk"

"mkfs.lustre --mdt --fsname=lustre --index=0 --servicenode=NID1 --servicenode=NID2 --mgsnode=mgsNID1 --mgsnode=mgsNID2 /dev/mdt-disk"

Possible placement: Section 13.10. Specifying NIDs and Failover

The examples given there almost cover the case, but the given command for mds0 will not work for separate mgs and mdt partitions, since the --mgsnode specification is missing.
Giving instead only 2 --mgsnode= specifications defines only the failover nids for the MGS, not the ones for the MDT. Even if MGS and MDT are run always from the same machine, i.e. if "mgsNID1" and "NID1" from my example command are the same, failover does not work, unless this nid is also specified as a --servicenode

Attentive reading of the manual might give the necessary clues right now, but seeing all options together in an example makes things by far easier.

Issue Links

• is related to: LUDOC-274 Add mkfs.lustre example for multi-hom...