On 09. nov. 2017 22:52, Marc Roos wrote:
I added an erasure k=3,m=2 coded pool on a 3 node test cluster and am
getting these errors.
pg 48.0 is stuck undersized for 23867.000000, current state
active+undersized+degraded, last acting [9,13,2147483647,7,2147483647]
pg 48.1 is stuck undersized for 27479.944212, current state
active+undersized+degraded, last acting [12,1,2147483647,8,2147483647]
pg 48.2 is stuck undersized for 27479.944514, current state
active+undersized+degraded, last acting [12,1,2147483647,3,2147483647]
pg 48.3 is stuck undersized for 27479.943845, current state
active+undersized+degraded, last acting [11,0,2147483647,2147483647,5]
pg 48.4 is stuck undersized for 27479.947473, current state
active+undersized+degraded, last acting [8,4,2147483647,2147483647,5]
pg 48.5 is stuck undersized for 27479.940289, current state
active+undersized+degraded, last acting [6,5,11,2147483647,2147483647]
pg 48.6 is stuck undersized for 27479.947125, current state
active+undersized+degraded, last acting [5,8,2147483647,1,2147483647]
pg 48.7 is stuck undersized for 23866.977708, current state
active+undersized+degraded, last acting [13,11,2147483647,0,2147483647]
Mentioned here
http://lists.ceph.com/pipermail/ceph-users-ceph.com/2016-May/009572.html
is that the problem was resolved by adding an extra node, I already
changed the min_size to 3. Or should I change to k=2,m=2 but do I still
then have good saving on storage then? How can you calculate saving
storage of erasure pool?
minimum nodes for a cluster is k+m and with that you have no nodes for
additional failure domain. IOW, if a node fail your cluster is degraded
and can not heal itself.
having ceph heal on failures is kind of one one of the best things about
ceph. so when choosing how many nodes to have in your cluster, you need
to think: k + m + how many node failures do i want to tolerate without
stressing = minimum number of nodes
basically with a 3 node cluster, you can either run 3x replication or
k=2 + m=1
to look for space saving you can read
http://ceph.com/geen-categorie/ceph-erasure-coding-overhead-in-a-nutshell/
kind regards
Ronny Aasen
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