Do you want to verify / check / see if you Mailbox Database is mounted or not?
Just do a check with powershell!
Open your Exchange Management Shell and use a combination of Get-MailboxDatabase with the -status option and you find the Mount-status (True/False) in Mounted attribute.
Put that all together in one command, you probably want something like :
Get-MailboxDatabase -Status | ft Name, Server, Mounted
You will get an output like this:
Name Server Mounted ---- ------ ------- Mail01-DB01 MAIL01 True Mail01-DB02 MAIL01 True Mail01-DB03 MAIL01 True
This can be easily used in a monitoring script!