Thnx a lot for making this clear! I thought 4 out of seven wouldn't be good because it's not an odd number... but I guess after I would have brought up the cluster with 4 MONs I could have removed one of the MONs to reach that (well, or add one)
thnx again Bernhard Am 06.09.2013 13:26:37, schrieb Jens Kristian Søgaard: > Hi, > > > In order to reach a quorum after reboot, you need to have more than half > > of yours mons running. > > with 7 MONs I have to have at least 5 MONS running? > No. 4 is more than half of 7, so 4 would be a majority and thus would be > able to form a quorum. > > > 4 would be more than the half but insufficient to reach a quorum. > I don't see why you think 4 would be insufficient. > > > But, would the cluster come up at all if I could get only 3 out of the 7 > > initial MONs up and running? > It wouldn't be able to form a quorum, and thus you would not be able to > use the cluster. > > > I.e. you have 2 mons out of 5 running for example - it will not reach a > > quorum because you need at least 3 mons to do that. > > Well, as I said, I had 3 MONs running, just the sequence in which they > > came up after the reboot was odd, > The number 3 was specifically for the example of having 5 mons in total. > > In your case where you have 7 mons in total, you need to have 4 running > to do anything meaningful. > > The order they are started in does not matter as such. > > > And do I need to make sure that a quorum capable number of MONs is up > > BEFORE I restart the OSDs? > No, that is not important. The OSDs will wait until the required number > of mons become available. > > > - stop MON / one after the other > > - start MON / in reverse order, last shutdown is first boot > It is not required to stop or start mons in a specific order. > > > central question remains, do I need 5 out of 7 MONs running or would 3 > > out of 7 be sufficient? > The magic number here is 4. > > -- > Jens Kristian Søgaard, Mermaid Consulting ApS, > j...@mermaidconsulting.dk> , > http://wwww.mermaidconsulting.com/ > > -- Bernhard Glomm IT Administration Phone: +49 (30) 86880 134 Fax: +49 (30) 86880 100 Skype: bernhard.glomm.ecologic Ecologic Institut gemeinnützige GmbH | Pfalzburger Str. 43/44 | 10717 Berlin | Germany GF: R. Andreas Kraemer | AG: Charlottenburg HRB 57947 | USt/VAT-IdNr.: DE811963464 Ecologic™ is a Trade Mark (TM) of Ecologic Institut gemeinnützige GmbH
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