When you deploy an instance of the Medical Imaging Server for DICOM, the following resources are important for performance in a production workload:
- App Service Plan: Hosts the Medical Imaging Service for DICOM.
- Azure SQL: Indexes a subset of the Medical Imaging Server for DICOM metadata to support queries and to maintain a queryable log of changes.
- Storage Account: Blob Storage which persists all Medical Imaging Server for DICOM data and metadata.
This resource provides guidance on Azure App Service, SQL Database and Storage Account settings for the Medical Imaging Server for DICOM. Note, these are recommendations but may not fit the exact needs of your workload.
The S1 tier is the default App Service Plan SKU enabled upon deployment. You can customize your App Service Plan SKU during deployment via the Medical Imaging Server for DICOM Quickstart Deploy to Azure. You can also update your App Service Plan after deployment. You can find instructions to that at Configure Medical Imaging Server for DICOM Settings.
Azure offers a variety of plans to meet your workload requirements. To learn more about the various plans, view the App Service pricing. To learn how to update your Azure App Service Plan, refer to Configure Medical Imaging Server for DICOM Settings.
The Standard tier of the DTU-based SQL performance tiers is enabled by default upon deployment. We recommend the DTU Purchase Model over the vCore model for the Medical Imaging Server for DICOM. In DTU-based SQL purchase models, a fixed set of resources is assigned to the database via performance tiers: Basic, Standard and Premium.
To review the various SQL Database Tiers from Azure, refer to Azure SQL Database Pricing. To learn how to update your Azure SQL Database tier, refer to Configure Medical Imaging Server for DICOM Settings.
For a production workload, we highly recommend configuring your Medical Imaging Server for DICOM to support geo-redundancy.
Azure Storage offers geo-redundant storage to ensure high availability even in the event of a regional outage. We highly recommend choosing an Azure Storage Account Sku that supports geo-redundancy if you are running a production workload. Azure storage offers two options for geo-redundant replication, Geo-zone-redundant-storage (GZRS) and Geo-redundant-storage (GRS). Refer to this article to decide which geo-redundant Azure Storage option is right for you: Use geo-redundancy to design highly available applications.
You can customize your Azure Storage Account SKU during deployment via the Medical Imaging Server for DICOM Quickstart Deploy to Azure. By default, Standard LRS is selected, which is Standard Locally Redundant Storage.
In addition to configuring geo-redundant Azure Storage, we recommend configuring active geo-replication for your Azure SQL Database. This allows you to create readable secondary databases of individual databases on a server in the same or different data center region. For a tutorial on how to configure this, see Creating and using active geo-replication - Azure SQL Database.
If you are testing out the Medical Imaging Server for DICOM and not running production workloads, we recommend using the S1 Azure App Service Tier alongside a Standard Azure SQL Database (S1, S2, S3). For a small system that does not require redundancy, with these tiers, you can spend as little as ~$70/month on Azure App Service & Azure SQL Database.
At these tiers with an appropriate mix of STOW, WADO and QIDO requests, you can expect to handle between 2,000 and 20,000 requests/minute and a response time under 1 second. Larger files, usage patterns that lean heavily to STOW, and poor bandwidth will reduce the number of requests per minute.
For a production workload, we recommend scaling up your Azure SQL Database to S12. For your Azure App Service, any Standard tier should be sufficient. If you are going into production, you also need to ensure your Medical Imaging Server for DICOM supports geo-redundancy. Refer to our geo-redundancy guidelines.
We recommend the S1 Standard Azure App Service Tier along side an Azure SQL Tier of S12. At these tiers with an appropriate mix of STOW, WADO and QIDO requests, you can expect to handle between 1,000 and 20,000 requests/minutes with response times under 400 ms. Larger files, usage patterns that lean heavily to STOW, and poor bandwidth will reduce the number of requests per minute. We recommend testing performance with your data and indented use.
If you workload requires bulk ingest of DICOM files or automated tooling to process DICOM files, we recommend scaling up your Azure App Service & Azure SQL Database to Premium tiers. If you are going into production, you also need to ensure your Medical Imaging Server for DICOM supports geo-redundancy. Refer to our geo-redundancy guidelines.
To support a large number of DICOM transactions per day, we recommend a P1v2 tier for Azure App Service alongside a P11 tier for Azure SQL Database. With excellent bandwidth, relatively small images and and appropriate mix of STOW, WADO and QIDO requests, you can expect to handle between 40,000 and 100,000 requests/minutes with response times under 200 ms. Larger files, usage patterns that lean heavily to STOW, and poor bandwidth will reduce the number of requests per minute. We recommend testing performance with your data and indented use.
In order to estimate workloads, automated scale tests were performed to simulate a production environment. The guidance in this document is a suggestion and may need to be modified to meet your environment. A few important notes to consider while configuring your service:
- Once you cross ~60% usage of your database, you will start to see a decline in performance.
- The scale tests done for the guidance in this document were performed using 500 KB DICOM files.
- Additionally, the scale tests were running with multiple concurrent callers. At fewer concurrent callers, you may have a higher request/minute and response time.
In this resource, we reviewed suggested guidance for Azure App Service tiers, Azure SQL tiers and Storage Account settings so that your Medical Imaging Server for DICOM can meet your workload requirements:
- To get started with the Medical Imaging Server for DICOM, Deploy to Azure.
- If you already have configured an instance of the Medical Imaging Server for DICOM, Configure your DICOM Server Settings.