-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, - From the documentation: Cache Tier readonly: Read-only Mode: When admins configure tiers with readonly mode, Ceph clients write data to the backing tier. On read, Ceph copies the requested object(s) from the backing tier to the cache tier. Stale objects get removed from the cache tier based on the defined policy. This approach is ideal for immutable data (e.g., presenting pictures/videos on a social network, DNA data, X-Ray imaging, etc.), because reading data from a cache pool that might contain out-of-date data provides weak consistency. Do not use readonly mode for mutable data. Does this mean that when a client (xen / kvm with a RBD volume) writes some data that the OSD does not mark the readonly cache dirty? In other words, what does 'weak consistency' mean here? Regards, Matthijs -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.22 (Darwin) iQIcBAEBAgAGBQJVCrcNAAoJEBXBjvSJ+ky+TK4P/2EbWeZICmzwS1RIeZZhRJL7 0tdcrzlETH7E6UZJS/dkOK/qea2ouXPipwnO8axj9nBc9ixHDx4ODTqeJ8t2Tm9T 6xtIcVtjatBsI9chkAcLhYK/vfLCTVeJFLwPeQLu/miYHmcn88eHuhkn/A2ARCdj MsmIYfTaV8VEY/4oUD2kMHog1yL/Io36vgAEgnMJrtSC2wQvyqiVO9ZVCaStkP8H ztIeKyhlCJRRWBA0PsvIiBX9brQhIPFIWDA8h+ypppA4YQLNsMq7xrNezrF4mSJt /keMwqUSeTsm7wkL1PLSAByosOjFsXKJkUHDsNtT6Dyzb5hzTTaA5XcWS7FFrA1p GnIEXGqf1Xk41zWFQhSzvUImxCtAAIF4DBDvndtEroMmofNLKGbfULKHJvvrkSKd uVswpSa7diA7dQXkUmisp/ZtoXuMtgA4WtJ4FmKRkCx1OpXHjKQjPm212ZD7hiQk z8zpasnQAvfE/0otvKaBXU5jTaMI8bhDaIZwY6wqpTxvok1MghsFMM619SQqy0nM tg0qf2Qb2NQIz0jvvlSsfhzyUmKP9WrSNVvYGeNCkxF1T0i1pRun1f4gMo+6lalj zLsoLufjgvd4w6e9G+p8eoLv4rcBEtNa8bX0o1vpC7k+Rh8STXcYeTSDAkU0xnf4 jgQXA5kan6ezsEMyqU7I =WCq1 -----END PGP SIGNATURE----- _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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