This question is a follow up to this.

We have a Windows Server 2008 R2 domain over a network that spans two different buildings, linked by a 100-Mbps point-to-point line. Over 60 users work in the organisation. We are planning to use DFS folders and DFS replication for file serving across the organisation. The estimated data volume is over 2 TB, and will grow at approximately 20% annually. The idea is to set up a DFS file server in each building and use DFS so that all the contents stay replicated over the 100-Mbps link.

We are now considering backup hardware and strategies. We are Dell customers and, after browsing the online Dell catalogue, I can see a number of backup hardware options. My main doubts are the following:

1. Would you go for a tape library, disk backup, or are there other options worth considering?
2. Would you perform batch backups (i.e. nightly) or would you use continuous backup (i.e. while users are working)?
3. Would you use a dedicated backup server to which the tape library (or any other backup device) is attached, or is there any other alternative way of doing things?

My experience with backup hardware and overall setup is limited, so I appreciate any good piece of advice that you may have. Thanks.