Jens (Mike) - thanks for the response here. This is starting to make sense, but one point I am still missing: I have a client which is Fedora18 and I have loaded the rbd kernel module, but the next commands on the Ceph website which involve getting a list of images use the rbd command which is not on the server: [root@ock tmp]# rbd list bash: rbd: command not found... Do I also need to install the Ceph packages to use rbd ? Also how does the client know how to connect to the cluster ? Should /etc/ceph/ceph.conf be copied over to the client ? Many thanks for your help Chris -----Original Message----- From: Jens Kristian Søgaard [mailto:jens@xxxxxxxxxxxxxxxxxxxx] Sent: 02 July 2013 20:27 To: Howarth, Chris [CCC-OT_IT] Cc: ceph-users@xxxxxxxx Subject: Re: Use of RDB Kernel module Hi Chris, > Does this then mean that I cannot access these block devices from > another server using libvirt/KVM ? No, qemu-kvm implement user-space access to rados block devices via librbd. So that will work fine even without the kernel module. Both locally on Ceph osd/mon servers as well as on remote clients. > 2) Is the kernel RBD module ever used on a remote client ? Yes, it is only meant for use on remote clients. I don't think it is officially supported to use it directly on the osds. It will probably work fine, but you could encounter error situations in low memory conditions. -- Jens Kristian Søgaard, Mermaid Consulting ApS, jens@xxxxxxxxxxxxxxxxxxxx, http://www.mermaidconsulting.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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