A couple of questions come to mind, including how are tape-based backups currently performing and meeting your needs? Are tape-based backups causing you problems such as long-running or failed backups, delayed file restoration, running out of tape capacity, fear of losing backup tapes or costs of manually handling tapes? Also, do you need to move copies of your data off site for safe keeping for disaster recovery protection or compliance purposes?
Based on the answers to these questions, you may be a candidate for a disk-based backup solution such as NAS, storage area network (SAN) or direct-attached storage. In the past, tape-based robotic libraries were very expensive; however, today you can find solutions for well under $10,000 in the market. That being said, disk drive prices continue to drop while capacities continue to increase, making for a good option for near-line and off-line backup mediums. NAS devices are also very affordable and can be used for a multi-tier backup strategy to back up clients to a NAS storage system and then back up the NAS device to some other medium, including removable tape or optical (CD or DVD).
The caveat to disk-based backup is that if you need to have a copy of your data off site, then you need to use remote mirroring or replication to a second disk drive or hosted storage service. Another option is disk-based removable backup devices that are appearing in the market combined with fixed disk for data protection. Regarding how big a company should be, I would focus more on how important your data is, how much data you have and how fast you need to be able recover it if needed.
Greg Schulz is founder and senior analyst of The StorageIO Group in Stillwater, Minn., and author of the book Resilient Storage Networks (Elsevier).