No. 3: What cost, virus protection?
The overhead of virus scanning varies widely from product to product. Make sure yours isn't a resource hogFollow @pvenezia
Virus protection on critical servers is a basic requirement, especially for Windows servers. The impact can be painful, however. Some virus scanners are more obtrusive than others and can reduce server performance significantly.
Try running performance tests with and without your virus scanner running to determine the impact. If you see a marked improvement without the scanner, it's time to look for another vendor. Also check specific features. Disable real-time scans, and quite often you'll bring performance up.