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Azure Event Hubs quotas and limits

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The following tables provide quotas and limits specific to Azure Event Hubs. For information about Event Hubs pricing, see Event Hubs pricing.

Common limits for all tiers

The following limits are common across all tiers.

Limit Notes Value
Size of an event hub name - 256 characters
Size of a consumer group name Kafka protocol doesn't require the creation of a consumer group.

Kafka: 256 characters

AMQP: 50 characters
Number of non-epoch receivers per consumer group - 5
Number of authorization rules per namespace Subsequent requests for authorization rule creation are rejected. 12
Number of calls to the GetRuntimeInformation method - 50 per second
Number of virtual networks (VNet) - 128
Number of IP Config rules - 128
Maximum length of a schema group name 50
Maximum length of a schema name 100
Size in bytes per schema 1 MB
Number of properties per schema group 1024
Size in bytes per schema group property key 256
Size in bytes per schema group property value 1024

Basic vs. standard vs. premium vs. dedicated tiers

The following table shows limits that are different for Basic, Standard, Premium, and Dedicated tiers.

Note

  • In the table, CU is capacity unit, PU is processing unit, and TU is throughput unit.
  • You can configure TUs for a Basic or Standard tier namespace or PUs for a Premium tier namespace.
  • When you create a dedicated cluster, one CU is assigned to the cluster. If you enable the Support scaling option while you create the cluster, you can scale out by increasing CUs or scale in by decreasing CUs for the cluster yourself. For step-by-step instructions, see Scale dedicated cluster. For clusters that don't support the Support scaling feature, submit a ticket to adjust CUs for the cluster.
Limit Basic Standard Premium Dedicated
Maximum size of Event Hubs publication 256 KB 1 MB 1 MB 1 MB
Number of consumer groups per event hub 1 20 100 1,000
No limit per CU
Number of Kafka consumer groups per namespace NA 1,000 1,000 1,000
Number of brokered connections per namespace 100 5,000 10,000 per PU

For example, if the namespace is assigned 3 PUs, the limit is 30,000.		 100,000 per CU
Maximum retention period of event data 1 day 7 days 90 days 90 days
Event storage for retention 84 GB per TU 84 GB per TU 1 TB per PU 10 TB per CU
Maximum TUs or PUs or CUs 40 TUs 40 TUs 16 PUs 20 CUs
Number of partitions per event hub 32 32 100 per event hub, but there's a limit of 200 per PU at the namespace level.

For example, if a namespace is assigned 2 PUs, the limit for total number of partitions in all event hubs in the namespace is 2 * 200 = 400.		 1,024 per event hub
2,000 per CU
Number of namespaces per subscription 1,000 1,000 1,000 1,000 (50 per CU)
Number of event hubs per namespace 10 10 100 per PU 1,000
Capture N/A Pay per hour Included Included
Size of compacted event hub N/A 1 GB per partition 250 GB per partition 250 GB per partition
Size of the schema registry (namespace) in megabytes N/A 25 100 1,024
Number of schema groups in a schema registry or namespace N/A 1: excluding the default group 100
1 MB per schema		 1,000
1 MB per schema
Number of schema versions across all schema groups N/A 25 1,000 10,000
Throughput per unit Ingress: 1 MB/sec or 1000 events per second
Egress: 2 MB/sec or 4,096 events per second		 Ingress: 1 MB/sec or 1,000 events per second
Egress: 2 MB/sec or 4,096 events per second		 No limits per PU * No limits per CU *

* Depends on factors such as resource allocation, number of partitions, and storage.

Note

You can publish events individually or batched. The publication limit (according to SKU) applies regardless of whether it's a single event or a batch. Publishing events larger than the maximum threshold will be rejected.

The following table shows the list of features that are available (or not available) in a specific tier of Azure Event Hubs.

Feature Basic Standard Premium Dedicated
Tenancy Multitenant Multitenant Multitenant with resource isolation Exclusive single tenant
Private link N/A Yes Yes Yes
Customer-managed key
(bring your own key)		 N/A N/A Yes Yes
Capture N/A Priced separately Included Included
Dynamic partition scale-out N/A N/A Yes Yes
Ingress events Pay per million events Pay per million events Included Included
Runtime audit logs N/A N/A Yes Yes
Availability zone Yes Yes Yes Yes
Geo-disaster N/A Yes Yes Yes
IP firewall N/A Yes Yes Yes

Note

Included in the table means the feature is available and there's no separate charge for using it.

Next steps

You can learn more about Event Hubs by visiting the following links: