Depends on how you use it - as RADOS object store? Or via radosgw? Or as RBD images? CephFS? Basically all RADOS object in the PGs on the OSD will be lost. That means all RBD images using those PGs will be lost (or have holes in them if you force it to, but basically you should consider them lost completely). Not sure about cephfs or radosgw, but it will be close to the first scenario. IMO doing this is a very very bad idea and I see no reason to use ceph to do this, too much abstraction because of durability, which you don’t have anyway… Jan > On 16 Jul 2015, at 12:58, Vedran Furač <vedran.furac@xxxxxxxxx> wrote: > > Hello, > > I'm experimenting with ceph for caching, it's configured with size=1 (so > no redundancy/replication) and exported via cephfs to clients, now I'm > wondering what happens is an SSD dies and all of its data is lost? I'm > seeing files being in 4MB chunks in PGs, do we know if a whole file as > saved through cephfs (all its chunks) are in a single PG (or at least in > a multiple PGs within a single OSD), or it might be spread over multiple > OSD, so in that case an SSD failure would entail effectively loosing > more than data than it fits on a single drive, or even worse, massive > corruption potentially affecting most of the content. Note that losing a > single drive and all of its data (so 1% in case of a 100 drives) isn't > an issue for me. However losing much more or files being silently > corrupted with holes in them is unacceptable. I would then have to go > with some erasure coding. > > Thanks, > Vedran > > > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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