Hi, To return to my comparison with SANs, on a SAN you have spare disks to repair a failed disk. On Ceph, you therefore need at least one more host (k+m+1). If we take into consideration the formalities/delivery times of a new server, k+m+2 is not luxury (Depending on the growth of your volume). ________________________________________________________ Cordialement, *David CASIER* ________________________________________________________ Le mar. 5 déc. 2023 à 11:17, Patrick Begou < Patrick.Begou@xxxxxxxxxxxxxxxxxxxxxx> a écrit : > Hi Robert, > > Le 05/12/2023 à 10:05, Robert Sander a écrit : > > On 12/5/23 10:01, duluxoz wrote: > >> Thanks David, I knew I had something wrong :-) > >> > >> Just for my own edification: Why is k=2, m=1 not recommended for > >> production? Considered to "fragile", or something else? > > > > It is the same as a replicated pool with size=2. Only one host can go > > down. After that you risk to lose data. > > > > Erasure coding is possible with a cluster size of 10 nodes or more. > > With smaller clusters you have to go with replicated pools. > > > Could you explain why 10 nodes are required for EC ? > > On my side, I'm working on building my first (small) Ceph cluster using > E.C. and I was thinking about 5 nodes and k=4 m=2. With a failure domain > on host and several osd by nodes, in my mind this setup may run degraded > with 3 nodes using 2 distincts osd by node and the ultimate possibility > to loose an additional node without loosing data. Of course with > sufficient free storage available. > > Am I totally wrong in my first ceph approach ? > > Patrick > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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