[Lustre-discuss] Failover for MGS

[Nathan Rutman]

Robert LeBlanc wrote:
> Ok, I feel really stupid. I've done this before without any problem, but I
> can't seem to get it to work and I can't find my notes from the last time I
> did it. We have separate MGS and MDTs. I can't seem to get our MGS to
> failover correctly after reformatting it.
>
> mkfs.lustre --mkfsoptions="-O dir_index" --reformat --mgs
> --failnode=192.168.1.253 at o2ib /dev/mapper/ldiskc-part1
>
>   
The MGS doesn't actually use the --failnode option (although it won't 
hurt).  You actually have to tell the other nodes
in the system (servers and clients) about the failover options for the 
MGS (use the --mgsnode parameter on servers, and mount address for 
clients).   The reason is because the servers must contact the MGS for 
the configuration information, and they can't ask the MGS where its 
failover partner is if e.g. the failover partner is the one that's running.

> We are running this on Debian, using the Lustre 1.6.3 debs from svn on Lenny
> with 2.6.22.12. I've tried several permutations of the mkfs.lustre command,
> specifing both nodes as failover, and both nodes as MGS and pretty much
> every other combination of the above. With the above command tunefs.lustre
> shows that failnode and mgsnode are the failover node.
>
> Thanks,
> Robert
>  
> Robert LeBlanc
> College of Life Sciences Computer Support
> Brigham Young University
> leblanc at byu.edu
> (801)422-1882
>
>
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