Hi, If you are using the experimental filesystem component of Ceph, and you use the less stable "numbered" Ceph releases, you should be aware of the following issue affecting the 0.82 development release: http://tracker.ceph.com/issues/8811 This issue introduces a risk of corruption when first starting MDS daemons after installing the 0.82 packages. A filesystem may be affected if: * You are upgrading an existing filesystem from an earlier version of Ceph (not if you are creating a new filesystem) * You have one or more MDS daemons configured with "mds standby replay = true" There are several ways to avoid this issue: 1 Ensure that the standby-replay MDS daemons are stopped while starting a single active MDS for the first time after upgrade. 2 Set "mds journal format = 0" in your configuration file before updating 3 Do not install 0.82, wait for the next development release Option 3 will be the best, unless you have a compelling need to install the latest development release. Don't forget: Ceph FS is currently not recommended for production data. Thanks, John
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