deployment slot performance?

Question

deployment slot performance?

Brent Mills 5

We are using deployment slots to host various project builds, however the performance is often extremely poor compared to the main slot. When I try scale up a slot it shows that it's on the same tier as our main slot, although this seems difficult to believe given the performance differential.

To gain a better performance experience, is our only option to create more web app instances?

RevelinoB 3,675 Reputation points

2023-04-27T09:59:51.07+00:00

Hi Brent, To improve performance in your Azure App Service deployment slots, you have various options available. One option is to consider scaling up the existing instances to higher performance tiers, providing more CPU power, memory, and resources to handle increased load. Another approach is to scale out by increasing the number of instances across your deployment slots, distributing the workload and improving performance. Additionally, optimizing your application's code and resources can significantly enhance performance. This involves identifying and addressing inefficiencies, slow database queries, and resource-intensive operations. Implementing a content delivery network (CDN), such as Azure CDN, can offload static content delivery, reducing latency and improving response times. Monitoring and diagnostics tools, such as Azure Application Insights, help identify performance bottlenecks, track resource usage, and troubleshoot issues in real-time. Lastly, optimizing database performance through query optimization, index creation, and reviewing database configurations can further improve overall performance. Remember to analyze your application's specific characteristics, traffic patterns, and resource requirements to determine the most effective combination of strategies for achieving the desired performance enhancements.

I hope this helps?
Brent Mills 5 Reputation points

2023-04-27T10:07:08.5933333+00:00

thanks for your reply RevelinoB. Your answer is related to general performance improvements of a web app instance. We have everything configured how we want and are happy with the performance of the main instance.
My question is whether there is some hidden difference between the web app and the deployment slots that would explain the performance differential?
Brent Mills 5 Reputation points

2023-04-28T08:49:52.9366667+00:00

Yes, thanks very much for your reply RevelinoB
Renaud Thoraval 0 Reputation points

2023-07-18T14:42:19.8333333+00:00

Hello @Brent Mills ! I had exactly the same issue with our slots on Azure in my company. I just resolved this issue by setting a different value AzureFunctionsWebHost__hostid on every slots. Our Azure function add a very long name and it's an issue because Azure computes an Id based on the first 32 characters of the name of your function (or web app). Our slots had exactly the same Id because of their long names.
I followed this document in order to set a new value for "hostId" on slots : https://github.com/Azure/azure-functions-host/wiki/Host-IDs#host-id-collisions

If you want to check if it's a naming issue like for us, you can go on the "Diagnose and solve problems" tab. It should be a critical issue.

I hope this helps you if you still have this problem. Otherwise, it may help someone who find this post because he has bad performances on his slots.

Bye !

Renaud

1 answer

Your answer

RevelinoB 3,675 Reputation points

2023-04-27T09:59:51.07+00:00

Hi Brent, To improve performance in your Azure App Service deployment slots, you have various options available. One option is to consider scaling up the existing instances to higher performance tiers, providing more CPU power, memory, and resources to handle increased load. Another approach is to scale out by increasing the number of instances across your deployment slots, distributing the workload and improving performance. Additionally, optimizing your application's code and resources can significantly enhance performance. This involves identifying and addressing inefficiencies, slow database queries, and resource-intensive operations. Implementing a content delivery network (CDN), such as Azure CDN, can offload static content delivery, reducing latency and improving response times. Monitoring and diagnostics tools, such as Azure Application Insights, help identify performance bottlenecks, track resource usage, and troubleshoot issues in real-time. Lastly, optimizing database performance through query optimization, index creation, and reviewing database configurations can further improve overall performance. Remember to analyze your application's specific characteristics, traffic patterns, and resource requirements to determine the most effective combination of strategies for achieving the desired performance enhancements.

I hope this helps?
Brent Mills 5 Reputation points

2023-04-27T10:07:08.5933333+00:00

thanks for your reply RevelinoB. Your answer is related to general performance improvements of a web app instance. We have everything configured how we want and are happy with the performance of the main instance.
My question is whether there is some hidden difference between the web app and the deployment slots that would explain the performance differential?
Brent Mills 5 Reputation points

2023-04-28T08:49:52.9366667+00:00

Yes, thanks very much for your reply RevelinoB
Renaud Thoraval 0 Reputation points

2023-07-18T14:42:19.8333333+00:00

Hello @Brent Mills ! I had exactly the same issue with our slots on Azure in my company. I just resolved this issue by setting a different value AzureFunctionsWebHost__hostid on every slots. Our Azure function add a very long name and it's an issue because Azure computes an Id based on the first 32 characters of the name of your function (or web app). Our slots had exactly the same Id because of their long names.
I followed this document in order to set a new value for "hostId" on slots : https://github.com/Azure/azure-functions-host/wiki/Host-IDs#host-id-collisions

If you want to check if it's a naming issue like for us, you can go on the "Diagnose and solve problems" tab. It should be a critical issue.

I hope this helps you if you still have this problem. Otherwise, it may help someone who find this post because he has bad performances on his slots.

Bye !

Renaud

Answer 1

Hi Brent, I apologize for the caused confusion. Let me try to clarify the potential hidden differences between the web app and the deployment slots that could contribute to a performance differential:

Traffic Allocation: By default, Azure evenly distributes incoming traffic across all deployment slots and the main instance. However, you have the option to configure traffic allocation differently for each slot using slot-specific routing rules. If certain slots are receiving a higher percentage of traffic than others, it can result in performance differences. Ensure that traffic allocation is configured consistently across all slots and the main instance.

Slot-Specific Configuration: Although I mentioned earlier to verify the consistency of configuration settings, it's important to reiterate that any differences in slot-specific configuration can affect performance. Check if there are any specific settings, such as scaling rules, instance size, or traffic routing configurations, that differ between the main instance and the deployment slots.

Cold Starts: Cold starts can occur when a deployment slot or instance is inactive for a period of time and then receives incoming traffic. If certain deployment slots are experiencing cold starts more frequently than others, it can impact performance. Cold starts can be mitigated by keeping the slots warm, for example, by implementing scheduled pings or using Azure Application Initialization.

Differences in Load or Resource Utilization: If the deployment slots are serving different workloads or experiencing varying levels of resource utilization, it can lead to performance differences. Check if there are any specific operations, background tasks, or third-party integrations that are exclusive to certain slots, as they may be impacting performance.

Platform Updates: Azure periodically rolls out updates to the underlying platform on which web apps are hosted. Although these updates aim to improve performance, they can occasionally result in differences in behavior or performance characteristics between the main instance and the deployment slots.

To investigate further, you can compare the performance metrics, logs, and diagnostics data between the main instance and the deployment slots.

I hope this answers your question?

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deployment slot performance?

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