RGW 动态的桶索引重分片¶
New in version Luminous.
A large bucket index can lead to performance problems. In order to address this problem we introduced bucket index sharding. Until Luminous, changing the number of bucket shards (resharding) needed to be done offline, from Luminous we support online bucket resharding.
Each bucket index shard can handle its entries efficiently up until reaching a certain threshold of entries. If this threshold is exceeded the system could encounter performance issues. The dynamic resharding feature detects this situation and increases automatically the number of shards used by the bucket index, resulting in the reduction of the number of entries in each bucket index shard. This process is transparent to the user.
The detection process runs:
1. When new objects are added to the bucket
2. In a background process that periodically scans all the buckets
This is needed in order to deal with existing buckets in the system that are not being updated.
A bucket that requires resharding is added to the reshard_log queue and will be
scheduled to be resharded later.
The reshard threads run in the background and execute the scheduled resharding, one at a time.
多站¶
动态重分片功能还不能在多站环境下使用。
配置选项¶
启用、禁用动态的桶索引重分片功能：
-rgw_dynamic_resharding: true/false, default: true.
Parameters to control the resharding process in Ceph configuration fie:
-rgw_reshard_num_logs: number of shards for the resharding log, default: 16
-rgw_reshard_bucket_lock_duration: duration of lock on bucket obj during resharding, default: 120 seconds.
-rgw_max_objs_per_shard: maximum number of objects per bucket index shard, default: 100000 objects.
-rgw_reshard_thread_interval: maximum time between rounds of reshard thread processing, default: 600 seconds
管理命令¶
把一个桶加进重分片队列¶
# radosgw-admin reshard add --bucket <bucket_name> --num-shards <new number of shards>
罗列重分片队列¶
# radosgw-admin reshard list
处理、调度一次桶重分片¶
# radosgw-admin reshard process
桶重分片状态¶
# radosgw-admin reshard status --bucket <bucket_name>
手动执行桶重分片¶
# radosgw-admin bucket reshard --bucket <bucket_name> --num-shards <new number of shards>
