HI,

I am using Exchange Server 2010 in my organization. I have around 4 MBX and 3 CAS + HT roles with around 9000 mailboxes. All are virtualised.

Currenytly, i am facing performance issues with my exchange server. i.e. sometimes messages get stuck in queue or RPC request errors, etc.

I am been given an assignment of doing analysis whether we need to increase hardware i.e. CPU or RAM on the server in order to cope up with increasing demand.

can anyone suggest me some tool or how to find out whether i need to increase RAM or CPU on exchange servers?

It would be the mailbox role requirements calculator to determine MBX sizing details.

https://gallery.technet.microsoft.com/office/Exchange-2010-Mailbox-Server-Role-