Hi, On 19/07/2016 13:06, Wido den Hollander wrote: >> Op 19 juli 2016 om 12:37 schreef M Ranga Swami Reddy <swamireddy@xxxxxxxxx>: >> >> >> Thanks for the correction...so even one OSD reaches to 95% full, the >> total ceph cluster IO (R/W) will be blocked...Ideally read IO should >> work... > That should be a config option, since reading while writes still block is also a danger. Multiple clients could read the same object, perform a in-memory change and their write will block. > > Now, which client will 'win' after the full flag has been removed? > > That could lead to data corruption. If it did, the clients would be broken as normal usage (without writes being blocked) doesn't prevent multiple clients from reading the same data and trying to write at the same time. So if multiple writes (I suppose on the same data blocks) are possibly waiting the order in which they are performed *must not* matter in your system. The alternative is to prevent simultaneous write accesses from multiple clients (this is how non-cluster filesystems must be configured on top of Ceph/RBD, they must even be prevented from read-only accessing an already mounted fs). > > Just make sure you have proper monitoring on your Ceph cluster. At nearfull it goes into WARN and you should act on that. +1 : monitoring is not an option. Lionel _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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