On 03/29/2017 12:03 AM, Forumulator V wrote:
Hi, I was going through the RGW code, and couldn't understand a few parts. i.) Where is zones and zonegroup information stored(on the backend)? Also do all RGW instances in a zone store objects on the same object storage cluster?
The multisite configuration (zone/zonegroup/period/realm) is stored as rados objects in the rgw.root pool (see RGW_DEFAULT_ZONE_ROOT_POOL and friends in rgw_rados.cc).
Generally, each zone will run in a separate ceph cluster. RGW instances within a zone will share the same storage.
But the zone itself contains the list of pool names used for its storage, so it's also possible to run multiple zones on the same ceph cluster without clobbering each others data - each zone will use separate pools by default.
ii.) What do zones and zonegroups really correspond to? Are they like regions in S3?
It's a similar concept to regions, but mostly within the context of replication. The first draft of rgw multisite actually used the term 'region' instead of zonegroup. You can think of a zonegroup as a replicated dataset - zones within a single zonegroup will replicate each others object data.
iii.) Where are the users and their metadata stored? Is it also on the backend?
Following up on point ii., users and buckets are considered 'metadata' by rgw multisite, and are replicated across all zonegroups. Users are stored as rados objects across several of the zone's pools (see the RGWZoneParams::user_*_pool fields in rgw_rados.h).
I'm sure the answers are there in the code, I understood some of it but not these parts. Thanks, Pranjal -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
I'm happy to answer more questions, if you have them. I also welcome suggestions for improving our existing documentation at http://docs.ceph.com/docs/master/radosgw/multisite/.
Casey -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
