Hello, On Wed, 23 Dec 2015 11:46:58 +0800 yuyang wrote: > ok, You give me the answer, thanks a lot. > Assume that a journal SSD failure means a loss of all associated OSDs. So in your case a single SSD failure will cause the data loss of a whole node. If you have 15 or more of those nodes, your cluster should be able to handle the resulting I/O storm from recovering 9 OSDs, but with just a few nodes you will have a severe performance impact and also risk data loss if other failures occur during recovery. Lastly, a 1:9 SSD journal to SATA ratio sounds also wrong when it comes to performance, your SSD would need be able to handle about 900MB/s sync writes, that's very expensive territory. Christan > But, I don't know the answer to your questions. > > Maybe someone else can answer. > > ------------------ Original ------------------ > From: "Loris Cuoghi";<lc@xxxxxxxxxxxxxxxxx>; > Date: Tue, Dec 22, 2015 07:31 PM > To: "ceph-users"<ceph-users@xxxxxxxxxxxxxx>; > Subject: Re: ceph journal failed？ > > Le 22/12/2015 09:42, yuyang a écrit : > > Hello, everyone, > [snip snap] > > Hi > > > If the SSD failed or down, can the OSD work? > > Is the osd down or only can be read? > > If you don't have a journal anymore, the OSD has already quit, as it > can't continue writing, nor it can assure data consistency, since writes > have probably been interrupted. > > The Ceph's community general assumption for a dead journal, is a dead > OSD. > > But. > > http://www.sebastien-han.fr/blog/2014/11/27/ceph-recover-osds-after-ssd-journal-failure/ > > How does this apply in reality? > Is the solution that Sébastien is proposing viable? > In most/all cases? > Will the OSD continue chugging along after this kind of surgery? > Is it necessary/suggested to deep scrub ASAP the OSD's placement groups? > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > <br></ceph-users@xxxxxxxxxxxxxx></lc@xxxxxxxxxxxxxxxxx> > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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