Hi, On 27/05/2015 22:34, Gregory Farnum wrote: > Sorry for the delay; I've been traveling. No problem, me too, I'm not really fast to answer. ;) >> Ok, I see. According to the online documentation, the way to close >> a cephfs client session is: >> >> ceph daemon mds.$id session ls # to get the $session_id and the $address >> ceph osd blacklist add $address >> ceph osd dump # to get the $epoch >> ceph daemon mds.$id osdmap barrier $epoch >> ceph daemon mds.$id session evict $session_id >> >> Is it correct? >> >> With the commands above, could I reproduce the client freeze in my testing >> cluster? > > Yes, I believe so. In fact, after some tests, the commands above evicts correctly the client (`ceph daemon mds.1 session ls` returns an empty array) but in the client side a new connection is automatically established as soon as the cephfs mountpoint is requested. In fact, I haven't succeeded in reproducing the freeze. ;) I have tried to stop the network in the client side (ifdown -a) and after few minutes (more than 60 seconds though), I have seen in the mds log "closing stale session client". But after a `ifup -a`, I have get back a cephfs connection and a mountpoint in good health. >> And could it be conceivable one day (for instance with an option) to be >> able to change the behavior of cephfs to be *not*-strictly-consistent, >> like NFS for instance? It seems to me it could improve performances of >> cephfs and cephfs could be more flexible concerning short network failure >> (not really sure for this second point). Ok it's just a remark of a simple >> and unqualified ceph-user ;) but it seems to me that NFS isn't strictly >> consistent and generally this not a problem in many use cases. Am I wrong? > > Mmm, this is something we're pretty resistant to. Ah ok, so I don't insist. ;) > In particular NFS > just doesn't make any efforts to be consistent when there are multiple > writers, and CephFS works *really hard* to behave properly in that > case. For many use cases it's not a big deal, but for others it is, > and we target some of them. Ok. Thanks Greg for your answer. -- François Lafont _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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