Azure Event Hubs quotas and limits
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: