Hi, If a disk containing an OSD is moved to another host, it is entirely possible that the objects it contains are violating a crush rule imposing that no object is replicated on the same host. Will this be taken care of as a side effect of updating the place of the OSD in the map ( https://github.com/ceph/ceph/blob/v0.61.9/src/upstart/ceph-osd.conf#L29 ) ?
Cheers On 23/10/2013 15:45, Loic Dachary wrote: > 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 <[email protected]> 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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