Change VM -> virtual machine

Author: anthonychu

articles/azure-functions/durable/durable-functions-cloud-backup.md

@@ -16,7 +16,7 @@ ms.author: azfuncdf
 
 In this sample, the functions upload all files under a specified directory recursively into blob storage. They also count the total number of bytes that were uploaded.
 
-It's possible to write a single function that takes care of everything. The main problem you would run into is **scalability**. A single function execution can only run on a single VM, so the throughput will be limited by the throughput of that single VM. Another problem is **reliability**. If there's a failure midway through, or if the entire process takes more than 5 minutes, the backup could fail in a partially completed state. It would then need to be restarted.
+It's possible to write a single function that takes care of everything. The main problem you would run into is **scalability**. A single function execution can only run on a single virtual machine, so the throughput will be limited by the throughput of that single VM. Another problem is **reliability**. If there's a failure midway through, or if the entire process takes more than 5 minutes, the backup could fail in a partially completed state. It would then need to be restarted.
 
 A more robust approach would be to write two regular functions: one would enumerate the files and add the file names to a queue, and another would read from the queue and upload the files to blob storage. This approach is better in terms of throughput and reliability, but it requires you to provision and manage a queue. More importantly, significant complexity is introduced in terms of **state management** and **coordination** if you want to do anything more, like report the total number of bytes uploaded.