I am not a Commvault rep. but I have experience with this.

What you are describing is our default setup. Unless a customer is really big, like over 10k users, then we keep access and index on the same VM.
So we have mostly 1 access/index VM for 1 customer. A few get 2 VMs but they both function as index nodes for all the customer’s M365 services.

In my opinion, the minimum requirements provided by Commvault in their documentation was made to avoid any potential problems or risks, if even tiny ones. We have not seen any issue with access/index VMs with specs way below the Commvaut recommended..

Some trial and error in the beginning, but we are now confident and have a balanced setup for all customers.

Hi @Amin91 

Index Servers and access node one same servers ?

2 powerfull Servers instead of 4.

Yes, this is certainly fine. The main concern of server requirements come from index server, log replays, etc. Its not uncommon for small data sets to have them combined. As you run backups check on the status page and make sure index status is update to date frequently to ensure you are not having any index playback issues.