Resource Consumption
This section describes how you, as a network administrator, can manage the consumption of Solace PubSub+ event broker resources on a Message VPN-basis. It also describes how you can set resource consumption limits for endpoints and how to control access to resources through client profiles.
To effectively plan how to manage event broker resources on a Message VPN‑basis, you should be familiar with the following:
- the system-level limits for Guaranteed Message delivery (for example, the maximum number of Message VPNs and the maximum combined number of queues and topic endpoints that are permitted)
- the maximum Guaranteed message ingress rates offered by the types of Solace PubSub+ software event brokers and Solace PubSub+ appliances used in your network. These rates are useful for determining what type of load Message VPNs could encounter.
In addition, if you are deploying event brokers in high-availability (HA) pairs and/or you are using replication for disaster-recovery site protection, you must ensure that the event brokers used in the HA pairs and/or replication clusters are evenly matched. That is, the event brokers that are provisioned should have equivalent operating limits so that if a failover occurs, the event broker that takes over service can support the same number of active client and Message VPNs that the out-of-service event broker was supporting.
Overbooking Event Broker Resources
You can configure Message VPNs on the Solace PubSub+ event broker so that:
- a full overbooking of all event broker resources is allowed
This means that any Message VPN can consume all available event broker resources. This is the event broker default.
- partial overbooking of event broker resources by Message VPNs is allowed
This means that no single Message VPN may consume all resources, but their configured resource consumption limits are high enough that, in combination, they could reach the system limit.
- no overbooking of event broker resources is allowed
This means that the sum of the configured consumption limits of all Message VPNs will not exceed the system limits.
Example Overbooking Scenarios
The scenarios below show examples of full, partial, and no overbooking scenarios for the maximum permitted number of client connections for a Solace PubSub+ appliance that has a total system limit of 9,000 simultaneous client connections:
- Fully-Overbooked Solace PubSub+ Event Brokers—Scenario A shows a fully overbooked event broker where the maximum permitted number of simultaneous client connections for each Message VPN is the same as maximum allowed for the entire event broker.
- Partially-Overbooked Solace PubSub+ Event Brokers—Scenario B shows a partially overbooked event broker. Although no single Message VPN allows the maximum permitted number of simultaneous client connections, the limits for the Message VPNs in combination exceed the system limit.
- Non-Overbooked Solace PubSub+ Event Brokers—Scenario C shows an event broker that is not overbooked. In this scenario the total maximum number of permitted simultaneous client connections for the entire event broker cannot be exceeded even when the values for each Message VPN are combined.
Setting Consumption Limits for VPNs
The table below lists the event broker configuration parameters that you can use to control the consumption of event broker resources on a per-Message VPN-basis.
| Resource Parameter | To set, see... |
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The maximum number of clients that can simultaneously connect to a Message VPN. The number of simultaneous client allowed for a Message VPN depends on the type of Solace PubSub+ event broker. |
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The maximum number of local client subscriptions that can be added to a Message VPN. |
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The maximum amount of system-level message spool disk space (in MB) that a Message VPN can use. The default value for the amount of disk storage permitted for a Message VPN is 0. Therefore, a value must be configured after a Message VPN is created so that it can spool messages. |
Message VPN-Level Guaranteed Messaging Configuration This is also configurable on a per-Guaranteed endpoint‑basis. |
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The maximum number of simultaneous transacted sessions allowed for a Message VPN. |
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The maximum number of queue and topic endpoints that can be created. |
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The maximum number egress flows (that is, Guaranteed message client receive flows) that can be created. |
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The maximum number ingress flows (that is, Guaranteed message client publish flows) that can be created. |
Setting Consumption Limits for Endpoints
The table below lists the event broker configuration parameters that you can use to control the consumption of event broker resources on a per-endpoint-basis.
| Resource Parameter | To set, see... |
|---|---|
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The maximum number of messages spooled to an endpoint that can be delivered to a client on a flow but remained unacknowledged the client. |
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The maximum message size (in bytes) permitted for the given durable message queue or topic endpoint. |
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The maximum amount of message spool disk space (in MB) that a queue or a topic endpoint is permitted to use. |
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Controlling Client Access to Resources
For each Message VPN, you can configure client profiles that set limits to control clientsʼ consumption of event broker resources. These client profiles are then applied to the client usernames that clients use to authentication with the event broker.
The following table lists client profile parameters that affect the amount of event broker resources clients can consume.
| Resource Parameter | To set, see... |
|---|---|
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The maximum number of client connections that can simultaneously connect with the same client username account. |
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The maximum number of local client subscriptions allowed for a single client connection. |
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The maximum depth of egress per-client priority queues, as measured in work units of 2048 bytes. |
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The maximum number of topics the event broker can track for performing the eliding function on each client connection. |
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Allow or deny clients to publish Guaranteed messages. Publishing Guaranteed messages consumes message spool resources in the Message VPN when messages are enqueued for delivery to Guaranteed Messaging consumers. You can adjust this parameter to ensure that only authorized clients are allowed to publish Guaranteed messages. |
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Allow or deny clients to create Guaranteed endpoints. You can adjust this parameter to ensure that only authorized clients are allowed to create Guaranteed endpoints. |
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The maximum number of durable and non‑durable queues and topic endpoints that can be owned by clients using the same client username. |
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Allow or deny clients to use transacted sessions using Solace messaging APIs. You can adjust this parameter to ensure that only authorized clients are allowed to create Guaranteed endpoints. |
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The maximum number of simultaneous transacted sessions allowed for a single client connection. |