SQL Server: SQL Server 2000, 2005 or 2008. SQL Server Express will work as well. VSys is not tied to any specific SQL Server versions and is not particularly sensitive to updates to the database. (No applications other than the basic database need to be installed on the server.)
Oracle: Oracle 9i or higher.
VSys does not require its own hardware, or even its own database instance, and will work properly sharing an instance with other applications. Disk space utilized depends entirely on your data, it’s a rare database that exceeds 1GB in the first year or two, and the 10GB mark is exceptionally unlikely to be reached.