Hi Joao, Thanks for this valuable information. Ok another problem, I want to remove the mon host from the cluster here is my mon dump output
root@vms2:~# ceph mon dump dumped monmap epoch 1 epoch 1 fsid 6ce085b5-1747-46f6-9fda-a3f1e8c75beb last_changed 0.000000 created 0.000000 0: 192.168.1.128:6789/0 mon.vms1 1: 192.168.1.129:6789/0 mon.vms2 I tried to remove the the mon.vms2 from the cluster following this document http://ceph.com/docs/master/rados/operations/add-or-rm-mons/ but again its not worked. root@vms2:~# service ceph -a stop mon.vms2 /etc/init.d/ceph: mon.vms2 not found (/etc/ceph/ceph.conf defines , /var/lib/ceph defines ) root@vms2:/etc/ceph# ceph mon remove mon.vms2 mon mon.vms2 does not exist or has already been removed Br. Umar On Tue, Dec 17, 2013 at 6:18 PM, Karan Singh <ksi...@csc.fi> wrote: > Thanks Joao for information. > > Many Thanks > Karan Singh > > > ----- Original Message ----- > From: "Joao Eduardo Luis" <joao.l...@inktank.com> > To: ceph-users@lists.ceph.com > Sent: Tuesday, 17 December, 2013 2:56:23 PM > Subject: Re: [ceph-users] After reboot nothing worked > > On 12/17/2013 09:54 AM, Karan Singh wrote: > > Umar > > > > *Ceph is stable for production* , there are a large number of ceph > > clusters deployed and running smoothly in PRODUCTIONS and countless in > > testing / pre-production. > > > > Since you are facing problems with your ceph testing , it does not mean > > CEPH is unstable. > > > > I would suggest put some time troubleshooting your problem. > > > > What i see from your logs -- > > > > 1) you have 2 Mons thats a problem ( either have 1 or have 3 to form > > quorum ) . Add 1 more monitor node > > Just to clarify this point a bit, one doesn't need an odd number of > monitors in a ceph cluster to reach quorum. This is a common > misconception. > > The requirement to reach quorum is simply to have a majority of monitors > able to talk to each other. If one has 2 monitors and both are able to > talk to each other they'll be able to form a quorum. > > Odd-numbers are advised however because one can tolerate as much > failures with less infrastructure. E.g., > > - for n = 1, failure of 1 monitor means loss of quorum > - for n = 2, failure of 1 monitor means loss of quorum > - for n = 3, failure of 1 monitor is okay; failure of 2 monitors means > loss of quorum > - for n = 4, failure of 1 monitor is okay; failure of 2 monitors means > loss of quorum > - for n = 5, failure of 2 monitors is okay; failure of 3 monitors means > loss of quorum > - for n = 6, failure of 2 monitors is okay; failure of 3 monitors means > loss of quorum > > etc. > > So you can see how you don't get any benefits, from an availability > perspective, by having either 2, 4 or 6 monitors when compared to having > 1, 3, 5. If your target however is replication, then 2 is better than 1. > > -Joao > > > > -- > Joao Eduardo Luis > Software Engineer | http://inktank.com | http://ceph.com > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Umar Draz Network Architect
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