Hi, As a conclusion to this thread and also because I realized that most people are unaware of the level of automation provided by ceph / udev, I just posted a quick summary : http://dachary.org/?p=2428
Cheers On 22/10/2013 19:31, Sage Weil wrote: > On Tue, 22 Oct 2013, Gregory Farnum wrote: >> On Mon, Oct 21, 2013 at 11:13 PM, Loic Dachary <l...@dachary.org> wrote: >>> >>> >>> On 21/10/2013 18:49, Gregory Farnum wrote: >>>> I'm not quite sure what questions you're actually asking here... >>>> In general, the OSD is not removed from the system without explicit >>>> admin intervention. When it is removed, all traces of it should be >>>> zapped (including its key), so it can't reconnect. >>>> If it hasn't been removed, then indeed it will continue working >>>> properly even if moved to a different box. >>> >>> If there is an external journal, the device containing the journal needs to >>> be moved with the device containing the data. If I read >>> ceph/src/upstart/ceph-osd.conf correctly, when the data device is plugged >>> in the new machine it will fail to start because the journal is not there >>> yet. When the journal device is plugged in, the ceph-osd.conf would be >>> called because udev rule in ceph/udev/95-ceph-osd.rules call ceph-disk >>> activate-journal. >>> >>> Is my understanding correct ? >> >> Well, after being wrong last time I'm a little reluctant to make >> pronouncements from memory, but that definitely sounds correct to me. > > Yep, that's how it's supposed to work. The activate-journal piece is > somewhat recent though (I think maybe it wasn't in place for cuttlefish?). > >> :) If I were doing an audit I'd want to look at what happens if there >> is a wrong journal in the correct location, etc. > > The ceph-osd will fail on start because the uuid/fsid doesn't match. > > sage > -- Loïc Dachary, Artisan Logiciel Libre All that is necessary for the triumph of evil is that good people do nothing.
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