> 3. You must use MDS from the start, because it's a metadata > structure/directory that only gets populated when writing files through > cephfs / FUSE. Otherwise, it doesn't even know about other objects and > therefore isn't visible on cephfs. > 4. MDS does not get updated when radosgw / S3 is used.
You can use MDS whenever you want to start using CephFS. CephFS and RadosGW are indepenent, they use different pools. Data added to RadosGW is not visible to CephFS, and data added to CephFS is not visible to RadosGW. It's all visible to RADOS, because both are implemented on top of RADOS. More on that later. > So my questions are: > * radosgw uses the ".bucket" pool for managing and controlling which buckets > there are? By default, RadosGW uses .rgw, .rgw.buckets.index, and .rgw.buckets. Once you start creating RadosGW users, it will create some more pools, depending on which of the features you're using. You can create different pools (using placement targets), and assign users and buckets to them. The common example is one user's data should be on SSDs, and another user should be on HDDs. > * a new bucket is written in ".bucket" and there will be an entry of some > sort in ".bucket-index" to keep track of objects created within that bucket? Actually, my .rgw.buckets.index pool has 0 bytes in use. It looks like everything goes into the .rgw.buckets pool. The bucket is just an object that contains a list of the files (and some metadata about those files). > * I.e., buckets and metadata about objects that live inside buckets are not > as such available from rados? (you can't query rados for these objects, > grouped by user/bucket?) Effectively, that's true. The objects are available using RADOS, but they're not in a human readable format. If you list the contents of the .rgw.buckets pool, you'll see stuff like: us-west-1.35026898.2__shadow__pcARf6VxB_ZPy0AwF-FKSADrV_H5l_m_2 us-west-1.43275004.2_5f33e39093fda01db84b6d32a1a1b3352b4b23f2778a756f751c0e9e51d62f6e us-west-1.43273412.2_669465eb9b41d94c4ebfc1bff7a26c9eee4ff065297f972132fc54942b160994 us-west-1.50224305.2__shadow__nJadmBD7-3loD4kBw7ug0HlO5RSxSLP_1 us-west-1.35026898.2__shadow__5EKY5xkrxmqr7iSrscl6emryM9DxBYx_1 us-west-1.43275004.2_70fcd7b628b7a13e92002b15dbfb7354668ada2eefbe9dfd2ffa5f5dd432ac59 us-west-1.51921289.1_989ecb8f4b786d60c4dc656c39220ea5cca76716789a1b2bfe66810ffd7846f3 ... RadosGW breaks every file up into a 4M chunk. With enough effort, you could reconstruct the bucket and object manually. I've done it once (to prove I could), but I don't plan to do it again. > * Are there alternatives for accessing the radosgw information besides going > through the S3 interface (command line)? I've been using s3cmd for command line access and general maintenance. It's a python script that talks to the S3 interface though, so you'll still need a website. _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
