Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Alan and John, This is *NOT* true, at least for 0.6.x. I'm still lacking the time to test 0.7.x though. DRBD has (used to have?) a legacy mode, which will boot DRBD devices as Secondary, leaving the decision of whom is Primary (the to-be-mirrored device) to Heartbeat (or another cluster manager). There are situations when the DRBD switches need to be controlled externally, thus (of course) compromising the latest-data-availability. This setup has been working for several weeks, and its described in my LTSP-HA HOWTO. See chapter 4.1.2 for further explanation - it was discussed in this list at the time of writing. Best regards,  http://republico.estv.ipv.pt/~nmct/ltsp/ha/ -- Nuno Tavares http://nthq.cjb.net/ >From: Alan Robertson <alanr at unix.sh> >To: Nuno Tavares <nunotavares at hotmail.com> >CC: drbd-user at linbit.com >Subject: Re: [DRBD-user] Clarification on How-To >Date: Thu, 16 Sep 2004 14:34:03 -0600 >Nuno Tavares wrote: >>>From: Alan Robertson <alanr at unix.sh> >>>To: John Lange <john.lange at bighostbox.com> >>>CC: drbd <drbd-user at linbit.com> >>>Subject: Re: [DRBD-user] Clarification on How-To >> >> >>>>Since the config files is not designed to indicate a primary node, how >>>>does drbd know which node shoul >> >> >>Each DRBD device keeps an internal state which will allow to determine >>which one is the most up-to-date (should read last-changed) node, between >>the two hosts connecting. This way the DRBD will always know which is the >>*best* DRBD to mirror from. >> >>You can surpass this behaviour by using a cluster manager (like >>Heartbeat), or doing it manually using drbdadm/drbdsetup. > >DRBD will never knowingly use out of date, and heartbeat will not override >that. Only humans can override that IIRC. On older implementations it >will refuse to fail over to the side with old data. On recent versions, it >will allow updates from either side, but it still uses the best copy of the >data (until they are updated to be the same). > > > > >-- > Alan Robertson <alanr at unix.sh> > >"Openness is the foundation and preservative of friendship... Let me claim >from you at all times your undisguised opinions." - William Wilberforce >_______________________________________________ >drbd-user mailing list >drbd-user at lists.linbit.com >http://lists.linbit.com/mailman/listinfo/drbd-user _________________________________________________________________ The new MSN 8: advanced junk mail protection and 2 months FREE* http://join.msn.com/?page=features/junkmail