Here are some useful Exchange 2010 Powershell commands I use regularly to report on where users are filling up our Exchange Databases.
(note 'MBX-SERVER' is your mailbox server name with the ' removed, "username" is the username and the quotes remain)
Database Size
Get-MailboxDatabase -Status | select name,databasesize,availablenewmailboxspace
Mailbox Size
Get-MailboxStatistics -Server 'MBX-SERVER' | Select DisplayName, ItemCount, TotalItemSize | Sort-Object TotalItemSize -Descending | Export-CSV C:\MailSize.csv
Drops to the csv on the C drive
Show top ten Mailbox folders with most Items on the Mailbox Server
Get-Mailbox –Server 'MBX-SERVER' -ResultSize Unlimited | Get-MailboxFolderStatistics | Sort-Object ItemsInFolder –Descending | Select-Object -First 10 | FT Identity,ItemsInFolder,FolderSize –Wrap
Top Ten folders in one users Mailbox by size
Get-Mailbox -Identity "username" -ResultSize Unlimited | Get-MailboxFolderStatistics -FolderScope All | Sort-Object FolderSize -Descending | Select-Object -First 10 | FT Identity,FolderSize,ItemsInFolder –wrap
