[ceph-users] How do you replace an OSD?
I just got my small Ceph cluster running. I run 6 OSDs on the same server to basically replace mdraid. I have tried to simulate a hard drive (OSD) failure: removed the OSD (out+stop), zapped it, and then prepared and activated it. It worked, but I ended up with one extra OSD (and the old one still showing in the ceph -w output). I guess this is not how I am supposed to do it? Documentation recommends manually editing the configuration, however, there are no osd entries in my /etc/ceph/ceph.conf So what would be the best way to replace a failed OSD? Dmitry ___ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
Re: [ceph-users] Ceph instead of RAID
This will be a single server configuration, the goal is to replace mdraid, hence I tried to use localhost (nothing more will be added to the cluster). Are you saying it will be less fault tolerant than a RAID-10? Ceph is a distributed object store. If you stay within a single machine, keep using a local RAID solution (hardware or software). Why would you want to make this switch? I do not think RAID-10 on 6 3TB disks is going to be reliable at all. I have simulated several failures, and it looks like a rebuild will take a lot of time. Funnily, during one of these experiments, another drive failed, and I had lost the entire array. Good luck recovering from that... I feel that Ceph is better than mdraid because: 1) When ceph cluster is far from being full, 'rebuilding' will be much faster vs mdraid 2) You can easily change the number of replicas 3) When multiple disks have bad sectors, I suspect ceph will be much easier to recover data from than from mdraid which will simply never finish rebuilding. 4) If we need to migrate data over to a different server with no downtime, we just add more OSDs, wait, and then remove the old ones :-) This is my initial observation though, so please correct me if I am wrong. Dmitry ___ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
[ceph-users] Ceph instead of RAID
Hello community, I am currently installing some backup servers with 6x3TB drives in them. I played with RAID-10 but I was not impressed at all with how it performs during a recovery. Anyway, I thought what if instead of RAID-10 I use ceph? All 6 disks will be local, so I could simply create 6 local OSDs + a monitor, right? Is there anything I need to watch out for in such configuration? Another thing. I am using ceph-deploy and I have noticed that when I do this: ceph-deploy --verbose new localhost the ceph.conf file is created in the current folder instead of /etc. Is this normal? Also, in the ceph.conf there's a line: mon host = ::1 Is this normal or I need to change this to point to localhost? Thanks for any feedback on this. Dmitry ___ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
