feat: Inkless doc updates

.github/vale/styles/config/vocabularies/Aiven/accept.txt

@@ -1,11 +1,15 @@
 188
 ACL
 ACLs
+ACU
+ACUs
 Addons
 africa
 AIInsights
 Aiven
 Aiven's
+AKU
+AKUs
 allowlist
 allowlists
 Altinity
@@ -140,7 +144,6 @@ GitHub
 go
 Google Cloud Platform
 google_columnar_engine_enabled
-google_columnar_engine_enabled
 google_columnar_engine_memory_size_percentage
 Gzipped
 gzipped
@@ -169,6 +172,7 @@ hypertables
 IdP
 IdPs
 InfluxDB
+Inkless
 InnoDB
 inodes
 Instana
@@ -259,7 +263,6 @@ pg_dump
 pgAdmin
 PGAudit
 PgBouncer
-pg_dump
 PGHoard
 pglookout
 pgoutput

docs/products/kafka/concepts/inkless-aku.md

@@ -0,0 +1,72 @@
+---
+title: AKU plans and scaling
+---
+import RelatedPages from "@site/src/components/RelatedPages";
+
+Inkless uses Aiven Kafka Units (AKUs) to help you size Apache Kafka services based on throughput instead of hardware resources.
+An AKU represents the amount of traffic a service can handle. You estimate the expected
+throughput when creating the service. This estimate determines the initial AKU level and
+the scaling range.
+
+## How AKUs work
+
+- Each AKU corresponds to a specific throughput capacity. It represents the compute and
+  memory resources required to meet that throughput.
+- The initial AKU level is derived from the expected throughput estimate provided during
+  service creation.
+- The service monitors throughput over time.
+- When throughput remains above the threshold for the current AKU level for a period of
+  time, the service scales up within your configured limits.
+- When throughput remains low for a sustained period, the service scales down.
+
+Scaling changes the number of AKUs in use, which affects AKU-hour billing. Scaling
+actions do not affect topic configuration or data retention.
+
+## Throughput measurement
+
+Inkless measures two types of traffic:
+
+- **Ingress:** Data written to topics by producers.
+- **Egress:** Data read from topics by consumers, connectors, and mirroring processes.
+
+Both ingress and egress affect the number of AKUs required. You can track ingress and
+egress usage in the Service utilisation view, which also shows the AKU thresholds.
+
+## Autoscaling limits
+
+Depending on your cloud provider and account, you can configure:
+
+- **Minimum AKUs:** The lowest capacity the service can scale down to.
+- **Maximum AKUs:** The highest capacity the service can scale up to.
+
+Inkless scales automatically within these limits. Scaling occurs only when
+throughput remains above or below a threshold for a sustained period.
+
+## Storage and AKUs
+
+Storage does not influence AKU scaling:
+
+- Diskless topics write directly to object storage.
+- Classic topics use local disk for recent data and move older segments to object storage
+  through tiered storage.
+
+Storage and compute scale independently, so you can adjust retention without changing
+AKU levels.
+
+## When to adjust AKU ranges
+
+Adjust your AKU limits when:
+
+- Workload throughput increases for sustained periods.
+- Traffic spikes begin to persist for longer periods.
+- Reducing costs during low-traffic periods requires a lower maximum AKU.
+- The workload needs a guaranteed minimum level of throughput.
+
+For details on how AKU usage affects billing, see [Billing](/docs/products/kafka/concepts/inkless-billing).
+
+
+<RelatedPages />
+
+- [Inkless overview](/docs/products/kafka/concepts/inkless)
+- [Billing for Inkless](/docs/products/kafka/concepts/inkless-billing)
+- [Create a Kafka service](/docs/products/kafka/create-kafka-service)

docs/products/kafka/concepts/inkless-billing.md

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+---
+title: Inkless billing
+sidebar_label: Billing
+description: Learn how billing works for Inkless Apache Kafka® on Aiven, including compute billed in AKUs, object storage costs, and topic ingress and egress charges.
+---
+
+import RelatedPages from "@site/src/components/RelatedPages";
+
+Inkless uses a usage-based billing model.
+You are charged for:
+
+- **Compute**, measured in Aiven Kafka Units (AKUs)
+- **Storage**, based on the amount of data retained in object storage
+- **Data movement**, based on topic ingress and egress
+
+:::note
+Inkless BYOC deployments continue to use the existing plans-based pricing model.
+:::
+
+## AKU-hours
+
+Compute charges are measured in AKU-hours.
+
+An AKU (Aiven Kafka Unit) represents the throughput capacity of the service. The service
+bills based on the number of AKUs in use over time, calculated in AKU-hours. When the
+service scales up or down, the AKU-hour charge updates to match the current AKU level.
+
+For details on how scaling works, see
+[AKU plans and scaling](/docs/products/kafka/concepts/inkless-aku).
+
+## Storage
+
+Storage charges are based on the amount of data retained in object storage.
+
+- Diskless topics store all retained data in object storage.
+- Classic topics keep some recent data on local disk before offloading it to
+  object storage.
+
+## Network usage
+
+Network charges apply to:
+
+- **Ingress:** Data written to topics
+- **Egress:** Data read by consumers, connectors, or mirroring processes
+
+Network usage is measured at the service level across all topics.
+
+:::note
+Only data written to and read from Kafka topics is billed.
+Data Kafka replicates between brokers for fault tolerance is not billed.
+:::
+
+<RelatedPages />
+
+- [Inkless overview](/docs/products/kafka/concepts/inkless)
+- [AKU plans and scaling](/docs/products/kafka/concepts/inkless-aku)
+- [Create a Kafka service](/docs/products/kafka/create-kafka-service)

docs/products/kafka/concepts/inkless.md

@@ -0,0 +1,71 @@
+---
+title: Inkless overview
+sidebar_label: Overview
+---
+
+import RelatedPages from "@site/src/components/RelatedPages";
+
+Inkless is Aiven’s cloud-native Apache Kafka® service that modernizes Kafka with diskless topics and object storage for data retention.
+It reduces operational overhead while preserving full compatibility with existing
+Kafka clients.
+
+Inkless runs on Kafka 4.x and uses Aiven Kafka Units (AKUs) to size services by throughput
+instead of hardware plans. It supports both classic and diskless topics within the same
+service.
+
+
+## Key differences from classic Kafka
+
+Inkless changes how Kafka services are sized, stored, and managed:
+
+- **Throughput-based sizing:** Services use AKUs instead of hardware plans and scale
+  within defined limits as throughput changes.
+- **Flexible storage:** Diskless topics store all data in object storage. Classic topics
+  use local disk with tiered storage enabled by default.
+- **Managed configuration:** Broker-level settings are fixed to maintain service
+  stability and allow automatic scaling.
+- **KRaft metadata management:** Inkless uses KRaft for metadata and consensus,
+  replacing ZooKeeper.
+- **Cloud availability:** Inkless is available on selected cloud providers, with support
+  expanding over time.
+- **Diskless topics:** Diskless topics are available only in Inkless services.
+
+## When to use Inkless
+
+Use Inkless when:
+
+- Workload throughput fluctuates and requires autoscaling.
+- Storage and compute must scale independently.
+- Your use cases require diskless topics for long-term retention or large datasets.
+- You need a simplified capacity model without hardware planning.
+
+Classic Kafka remains available for existing deployments and appears in the Aiven Console
+only for customers who already run Classic services.
+
+## Inkless capabilities
+
+Inkless supports:
+
+- High-throughput workloads by reducing cross-availability zone network traffic with diskless topics.
+- Workloads with fluctuating throughput through autoscaling.
+- Independent scaling of storage and compute.
+- Diskless topics for long-term retention and large datasets.
+- A simplified, throughput-based capacity model without hardware planning.
+
+
+## Existing Classic Kafka services
+
+Existing Classic Kafka services continue to run unchanged.
+
+Classic Kafka remains available only for existing deployments and appears in the
+Aiven Console only when a project already includes a Classic Kafka service.
+
+Upgrading or migrating an existing Classic Kafka service to Inkless is not supported at this time.
+Service type is fixed at creation. To use Inkless, create a Kafka service and select
+Inkless as the service type.
+<RelatedPages />
+
+- [Create a Kafka service](/docs/products/kafka/create-kafka-service)
+- [Diskless topics overview](/docs/products/kafka/diskless/concepts/diskless-overview)
+- [AKU plans and scaling](/docs/products/kafka/concepts/inkless-aku)
+- [Billing for Inkless](/docs/products/kafka/concepts/inkless-billing)