[DRBD-user] Apps cannot write for 15 seconds during failover

Michael Toler mike.toler at prodeasystems.com
Wed Jan 2 16:41:27 CET 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

(I buried this question in another post before the holidays and it didn't seem
to get any response, so I'm trying again.

       2  IBM Xeon blades as NFS/DRBD log servers setup as 
      20+ Blades running various packages (JBoss, Jabber, 
          Postgres, etc) logging 
          to the NFS log server.
      All blades running RH 4 ES.

Right now I have all of my processes connecting to the Primary 
side of a my DRBD setup.  I'm using this setup as a log server for 
processes on multiple blades on a blade server.  

When I do the HA switchover, my processes lock for about 15 seconds 
(when using soft mounted NFS directories) before continuing to write 
to the files their log files on the secondary server.    I had thought
 that since I moved the /var/lib/nfs directory to my drbd shared 
directory that the failover would be pretty much instantaneous.  
Do I have a problem in my setup somewhere or is 15 seconds for 
failover fairly standard?


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