>>What is the behavior of mongo when a shard is unavailable for some reason (crash or network partition) ? If shard3 is on the wrong side of a network partition and uses RBD, it will hang. Is it something that mongo will >>gracefully handle ? If one shard is down, I think the cluster is locked. That's why I thinked to add corosync/pacemaker to restart a mongod daemon on another host, migrate a vip, keeping the same /dev/rbd3 (as it can be shared on all nodes) for example. A little bit complex, but this mongodb replication is really buggy on high load. (Need to implement librados inside mongo ;) ----- Mail original ----- De: "Loic Dachary" <loic@xxxxxxxxxxx> À: "aderumier" <aderumier@xxxxxxxxx>, "ceph-users" <ceph-users@xxxxxxxx> Envoyé: Jeudi 12 Février 2015 11:12:02 Objet: Re: mongodb on top of rbd volumes (through krbd) ? Hi Alexandre, What is the behavior of mongo when a shard is unavailable for some reason (crash or network partition) ? If shard3 is on the wrong side of a network partition and uses RBD, it will hang. Is it something that mongo will gracefully handle ? I have no experience in this but I'm curious about this use case :-) Cheers On 12/02/2015 05:55, Alexandre DERUMIER wrote: > Hi, > > I'm currently running a big mongodb cluster, around 2TB, (sharding + replication). > > And I have a lot of problems with mongo replication (out of syncs and need to full replicate again and again datas between my mongo replicats). > > > So, I thinked to use rbd to replicate the storage and keep only sharding on mongo. (maybe with some kind of shard failover between nodes with corosync). > > NODE1 NODE2 NODE3 > ----- ----- ------ > [shard1] [shard2] [shard3] > | | | > | | | > /dev/rbd0 /dev/rbd1 /dev/rbd2 > > > Has somebody already tested such kind of setup with mongo ? > > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Loïc Dachary, Artisan Logiciel Libre _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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