Resharding bucket index dynamically

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You can reshard the bucket index dynamically by adding the bucket to the resharding queue. It gets scheduled to be resharded. The reshard threads run in the background and runs the scheduled resharding, one at a time.

Prerequisites

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A running IBM Storage Ceph cluster.
A Ceph Object Gateway installed.

Procedure

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Set the rgw_dynamic_resharding parameter is set to true.

Example
```
[ceph: root@host01 /]# radosgw-admin period get
```
Optional: Customize Ceph configuration using the following command:

Syntax
```
ceph config set client.rgw OPTION VALUE
```
Replace OPTION with the following options:
- rgw_reshard_num_logs: The number of shards for the resharding log. The default value is 16.
- rgw_reshard_bucket_lock_duration: The duration of the lock on a bucket during resharding. The default value is 360 seconds.
- rgw_dynamic_resharding: Enables or disables dynamic resharding. The default value is true.
- rgw_max_objs_per_shard: The maximum number of objects per shard. The default value is 100000 objects per shard.
- rgw_reshard_thread_interval: The maximum time between rounds of reshard thread processing. The default value is 600 seconds.
Example
```
[ceph: root@host01 /]# ceph config set client.rgw rgw_reshard_num_logs 23
```

Add a bucket to the resharding queue:

Syntax

radosgw-admin reshard add --bucket BUCKET --num-shards NUMBER

Example

[ceph: root@host01 /]# radosgw-admin reshard add --bucket data --num-shards 10

List the resharding queue:

Example

[ceph: root@host01 /]# radosgw-admin reshard list

Check the bucket log generations and shards:

Example

[ceph: root@host01 /]# radosgw-admin bucket layout --bucket data
{
    "layout": {
        "resharding": "None",
        "current_index": {
            "gen": 1,
            "layout": {
                "type": "Normal",
                "normal": {
                    "num_shards": 23,
                    "hash_type": "Mod"
                }
            }
        },
        "logs": [
            {
                "gen": 0,
                "layout": {
                    "type": "InIndex",
                    "in_index": {
                        "gen": 0,
                        "layout": {
                            "num_shards": 11,
                            "hash_type": "Mod"
                        }
                    }
                }
            },
            {
                "gen": 1,
                "layout": {
                    "type": "InIndex",
                    "in_index": {
                        "gen": 1,
                        "layout": {
                            "num_shards": 23,
                            "hash_type": "Mod"
                        }
                    }
                }
            }
        ]
    }
}

Check bucket resharding status:

Syntax

radosgw-admin reshard status --bucket BUCKET

Example

[ceph: root@host01 /]# radosgw-admin reshard status --bucket data

Process entries on the resharding queue immediately:

[ceph: root@host01 /]# radosgw-admin reshard process

Cancel pending bucket resharding:

Warning: You can only cancel pending resharding operations. Do not cancel ongoing resharding operations.

Syntax
```
radosgw-admin reshard cancel --bucket BUCKET
```
Example
```
[ceph: root@host01 /]# radosgw-admin reshard cancel --bucket data
```

Verification

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Check bucket resharding status:

Syntax

radosgw-admin reshard status --bucket BUCKET

Example

[ceph: root@host01 /]# radosgw-admin reshard status --bucket data

Reference

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For more information, see the following: