Zone Features

Some features require support from all cooperating radosgws before they can be enabled. Each zone lists its supported_features, and each zonegroup lists its enabled_features. Before a feature can be enabled in the zonegroup, it must be supported by all of its zones.

On creation of new zones and zonegroups, all known features are supported and some features (see table below) are enabled by default. After upgrading an existing zone, however, new features must be enabled manually.

Supported Features

Feature	Release	Default
resharding	Reef	Enabled
compress-encrypted	Reef	Disabled
notification_v2	Squid	Enabled

resharding

This feature allows buckets to be resharded in a multisite configuration without interrupting the replication of their objects. When rgw_dynamic_resharding is enabled, it runs on each zone independently, and zones may choose different shard counts for the same bucket. When buckets are resharded manually with radosgw-admin bucket reshard, only that zone’s bucket is modified. A zone feature should only be marked as supported after all of its RGWs and OSDs have upgraded.

Note

Dynamic resharding is not supported in multisite deployments prior to the Reef release.

compress-encrypted

This feature enables support for combining Server-Side Encryption and Compression on the same object. Object data gets compressed before encryption. Prior to Reef, multisite would not replicate such objects correctly, so all zones must upgrade to Reef or later before enabling.

Warning

The compression ratio may leak information about the encrypted data, and allow attackers to distinguish whether two same-sized objects might contain the same data. Due to these security considerations, this feature is disabled by default.

notification_v2

This feature opts in to a new “v2” metadata format for bucket notifications and topics. Unlike “v1”, this format is supported by multisite replication and can scale to many topics.

Once this feature is enabled on all zonegroups in the realm, a background process will convert existing v1 topics and bucket notifications into their v2 format.

Commands

Add support for a zone feature

On the cluster that contains the given zone:

radosgw-admin zone modify --rgw-zone={zone-name} --enable-feature={feature-name}
radosgw-admin period update --commit

Note

The period update command only works if the zone belongs to a realm. Otherwise, all radosgws will need to restart before they notice the change.

Remove support for a zone feature

On the cluster that contains the given zone:

radosgw-admin zone modify --rgw-zone={zone-name} --disable-feature={feature-name}
radosgw-admin period update --commit

Enable a zonegroup feature

On any cluster in the realm:

radosgw-admin zonegroup modify --rgw-zonegroup={zonegroup-name} --enable-feature={feature-name}
radosgw-admin period update --commit

Disable a zonegroup feature

On any cluster in the realm:

radosgw-admin zonegroup modify --rgw-zonegroup={zonegroup-name} --disable-feature={feature-name}
radosgw-admin period update --commit

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