Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 01/07/2011 03:36 AM, Felix Frank wrote: >> The risk here, though, is with split-brains. >> >> Consider this; >> >> You have two partition on your DRBD; one each for two VMs. In the course >> of normal operation you have one VM running on NodeA and the other VM >> running on NodeB. DRBD Primary/Primary will allow this. Then though, you >> have a split brain. >> >> At the moment of the split brain, unless you've configured a stonith >> device in DRBD, either side will go off on their own and your VMs will >> continue to run. From this point on, both sides are "more up to date" >> than the other. This is because both are writing to their VM's partition. > > <snip> > > Wasn't the intention to have one LV+DRBD per VM? > > Doing dual-primary have the nodes work with distinct parts of the same > DRBD doesn't sound like much of a good idea, because of the scenario you > described. > > It *is* a good idea to allow dual-primary when using one LV per VM > though, so that live-migration is available, afaik. > > Regards, > Felix You are right. If you have one DRBD resource per LV/VM, then you will avoid the scenario I described. -- Digimer E-Mail: digimer at alteeve.com AN!Whitepapers: http://alteeve.com Node Assassin: http://nodeassassin.org