@YayeFatouAwaFall-4090 Thanks for posting your query on Microsoft Q&A.
If you want to move from IaaS to PaaS for your application, you can still use Azure File Sync as it supports both IaaS and PaaS.
However, there are other alternatives such as Azure Blob Storage which is a PaaS solution that provides scalable object storage for unstructured data. Azure Blob storage is a fully-managed cloud storage solution that is optimized for storing unstructured data like files, images, videos, and audio. You can use Blob storage to store files that are used by your application and then access them using the Azure Storage Blob REST API or SDKs. This option will allow you to decouple your file storage from your application, which can provide better scalability and performance.
You can also use Azure Data Lake Storage Gen2 which is a PaaS solution that provides scalable data lake storage for big data analytics workloads.
Another option is to use Azure App Service with Azure Storage. You can use Azure Storage as an alternative to Azure File Sync to store files and then access them from your application running on App Service. App Service can automatically scale up or down based on demand, which can provide better performance and cost savings.
All these alternatives will require some modification to your application along with cost and performance implications as well.
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