DOC-6874: Document smooth scaling prerequisites on Cloud clustering page - #3687
DOC-6874: Document smooth scaling prerequisites on Cloud clustering page#3687mich-elle-luna wants to merge 2 commits into
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Adds a Smooth scaling section covering prerequisites (new DB, Redis hashing policy, DB version 8.4+, cluster version 8.0.18+, HA required), unsupported cases (Active-Active, Flex, existing DBs), and backward compatibility guidance for when it is safe to enable. Updates the Redis hashing policy description to link to the new section. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
| - Your application uses binary data as key names. | ||
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| The Redis hashing policy allows for faster scaling where available. | ||
| The Redis hashing policy allows for [faster scaling](#smooth-scaling) where available. |
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Change "faster scaling" to "Smooth Scaling"
| @@ -194,4 +194,43 @@ After you select OSS Cluster API, you can select **Use external endpoint** if yo | |||
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| The OSS Cluster API is supported only when a database uses the [standard hashing policy](#standard-hashing-policy). | |||
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OSS Cluster API is supported for both the Standard hashing policy and the Redis hashing policy
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| ## Smooth scaling {#smooth-scaling} | ||
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| Smooth scaling is an improved resharding method for Redis Cloud Pro databases. Compared to legacy resharding, it is significantly faster, reduces latency spikes and disconnects during scaling, and supports scaling down (decreasing shard count). Legacy resharding always doubles the shard count and does not support scale-down. |
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using the term "legacy" is problematic.
GPT suggested "traditional"...
Remove "and supports scaling down (decreasing shard count)". From the customers POV scaling down was always supported.
Remove "Legacy resharding always doubles the shard count and does not support scale-down."
That's not something we want to tell the world....
| Smooth scaling is an improved resharding method for Redis Cloud Pro databases. Compared to legacy resharding, it is significantly faster, reduces latency spikes and disconnects during scaling, and supports scaling down (decreasing shard count). Legacy resharding always doubles the shard count and does not support scale-down. | ||
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| {{< note >}} | ||
| Smooth scaling is only available for new databases. Existing databases continue to use legacy resharding. |
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It's not just for new DBs, it's for any DB which meets the prerequisites (de facto, there are only few of those).
i.e. "Smooth scaling is available for databases which meet the following prerequisites... other databases continue to use traditional scaling".
(not resharding)
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| | Requirement | Detail | | ||
| |---|---| | ||
| | New database | Smooth scaling cannot be enabled on an existing database. | |
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"Smooth scaling cannot be enabled on an existing database."
the users don't enable ASM. They only have to make sure that the DB meets the preconditions.
Once they do, Smooth Scaling will be used when it's time to scale a DB.
Also, there could be existing DBs which meet the preconditions, so "new database" is not accurate.
| | Requirement | Detail | | ||
| |---|---| | ||
| | New database | Smooth scaling cannot be enabled on an existing database. | | ||
| | Hashing policy | Must use the [Redis hashing policy](#redis-hashing-policy). Standard and Custom hashing policies are not supported. | |
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"Standard and Custom hashing policies are not supported."
the policies are still supported, but traditional scaling will be used
| | New database | Smooth scaling cannot be enabled on an existing database. | | ||
| | Hashing policy | Must use the [Redis hashing policy](#redis-hashing-policy). Standard and Custom hashing policies are not supported. | | ||
| | Database version | Redis 8.4 or later. | | ||
| | Cluster version | Redis Cloud cluster version 8.0.18 or later. | |
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Remove "cluster version" - RC users are not aware if this internal version
| | Hashing policy | Must use the [Redis hashing policy](#redis-hashing-policy). Standard and Custom hashing policies are not supported. | | ||
| | Database version | Redis 8.4 or later. | | ||
| | Cluster version | Redis Cloud cluster version 8.0.18 or later. | | ||
| | High availability | HA must be enabled. Without HA, a database restart during scaling risks data loss. | |
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Remove the HA line.
Fortunately, this limitation was already removed.
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| ### Backward compatibility | ||
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| Enabling smooth scaling puts shards into cluster mode, which enforces the same-slot requirement for multi-key commands. For most new databases this is safe to enable immediately, but there are cases where you should wait: |
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"Backward compatibility" section:
The current content is not relevant for users. It is all managed internally by RC. Customers don't need to care if it's safe or not to enable the feature.
However, the below is relevant for this section.
Customers do not need to make any changes to their application code. The changes related to ASM and Smooth Scaling are implemented internally and do not affect RESP commands or how clients connect to and communicate with the database
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@mich-elle-luna I've added comments, thanks.
- Capitalize "Smooth Scaling" as a proper noun (line 103) - Fix OSS Cluster API hashing policy support: both Standard and Redis hashing policies are supported (pre-existing inaccuracy) - Replace "legacy" with "traditional" throughout - Remove scale-down comparison claims (not a customer-visible differentiator) - Reframe availability: any DB meeting prerequisites, not "new DBs only" - Reframe prerequisites as automatic conditions, not user-enabled settings - Remove "New database" prerequisite row (inaccurate framing) - Update hashing policy detail to clarify Standard/Custom use traditional scaling - Remove "Cluster version" row (internal detail, not visible to RC users) - Remove "High availability" row (limitation was removed) - Replace backward compatibility table with a note that no app code changes are needed Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
🧠 Redis MemoryFound 5 related items from repository history:
Memory updated at 54b9aaa |
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Adds a Smooth scaling section covering prerequisites (new DB, Redis hashing policy, DB version 8.4+, cluster version 8.0.18+, HA required), unsupported cases (Active-Active, Flex, existing DBs), and backward compatibility guidance for when it is safe to enable. Updates the Redis hashing policy description to link to the new section.
Note
Low Risk
Documentation-only changes to RC clustering guidance; no runtime, auth, or application code paths.
Overview
Documents Smooth scaling on the Redis Cloud clustering page: what it is (faster resharding with fewer latency spikes), when it applies automatically, what is excluded, and that apps need no code changes.
The new section lists prerequisites (Redis hashing policy, Redis 8.4+), calls out unsupported cases (Active-Active, Flex, Standard/Custom hashing on existing DBs), and links from the Redis hashing policy bullet (replacing generic “faster scaling” wording). OSS Cluster API support is broadened to include the Redis hashing policy, not only Standard.
The diff also updates the internal
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