[lustre-discuss] OST mount with failover MDS

Thomas Roth t.roth at gsi.de
Wed Mar 17 04:56:43 PDT 2021

Hi all,

I wonder if I am seeing signs of network problems when mounting an OST:

tunefs.lustre --dryrun tells me (what I know from my own format command)
 >Parameters: mgsnode= at o2ib5: at o2ib5

These are the nids for our MGS+MDT0, there are two more pairs for MDT1 and MDT2.

I went step-by-step, modprobing lnet and lustre, and checking LNET by 'lnet ping' to the active MDTs, 
which worked fine.

However, mounting such an OST (e.g. after a crash) at first prints a number of
 > LNet: 19444:0:(o2iblnd_cb.c:3397:kiblnd_check_conns()) Timed out tx for at o2ib5: 0 seconds

and similarly for the failover partners of the other two MDS.

Should it do that?

Imho, LNET to a failover node _must_ fail, because LNET should not be up on the failover node, right?

If I started LNET there, and some client does not get an answer quickly enough from the acting MDS, it 
would try the failover, LNET yes but Lustre no - that doesn't sound right.


Thomas Roth
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