I had a few issues with this, so I thought I would put the script I used which moved the OWA site collection to another content database. This is very important to do as it affects the overall size of your content database. This should be a part of any large deployment and really, should be on a separate LUN as heavy use could affect the performance of your default site ( but that is for another article ).
Here is the script:
$webapp = "http://sharepoint"
$newDB = New-SPContentDatabase -Name Owa_Cache -WebApplication $webapp -DatabaseServer DATABASENAME\sharepoint
Get-SPOfficeWebAppsCache -WebApplication $webapp | Move-SPSite -DestinationDatabase $newDB
This will create a new content database called Owa_cache in the DATABASENAME\SharePoint instance, attached to the http://sharepoint web application.
Here is the script:
$newDB = New-SPContentDatabase -Name Owa_Cache -WebApplication $webapp -DatabaseServer DATABASENAME\sharepoint
Get-SPOfficeWebAppsCache -WebApplication $webapp | Move-SPSite -DestinationDatabase $newDB
This will create a new content database called Owa_cache in the DATABASENAME\SharePoint instance, attached to the http://sharepoint web application.