We're a relatively small organization (25 users, 9 servers, everything Windows-based) and we've been using tape backup since the beginning; currently we're using Backup Exec to perform the backup.
We've been looking into getting larger devices to store data (NAS) and Backup Exec apparently has a problem with backing up those devices unless they have an O/S installed on them. This got us thinking: do we even need to back up to tape any longer? We have a 7-year data retention schedule, so perhaps we could just use hard drives and (shudder) Windows backup.
Any thoughts on this? Is it reasonable to assume that rotated external drives are adequate for backing up data reliably?
Update: A full back up is about 700 GB. Our daily incremental takes much less (of course).
Personally I trust tapes for long term storage more than I trust hard drives. Also, unless my math is wrong, The cost to store data on tapes is much cheaper than hard drives. I can store up to 400GB of compressed data on an LTO2 tape for $35.00 while an external hard drive with that capacity will cost roughly twice that.
While I currently use NAS and have had to use tape backup (Bacula/Amanda/BackupExec) for work, tape is a necessity if for only the ability to move the tape offsite and into a facility like a safe deposit box or give to a vendor like IronMountain. If the office is robbed or burns down to the ground, now what good is a hard drive/NAS then?
Depending on how much data is being backed up (full/incremental), I'd say use the tape to backup critical day-to-day business operations files, emails, whatever and keep rotating that tape offsite. Tape still has a very good lifespan (and storage capacity) and while HDDs/NAS devices are much faster and readily available, tape's main advantage over them is portability. I would say in terms of reliability that tapes need to be tested on a regular basis. I've had tapes go bad and by making it a point to always test tapes as part of my routine, I haven't had any issues with tape since.
The one caveat to tape of course is cloud storage but that involves bandwidth, security, privacy, a large amount of trust, etc. etc. - issues that are probably out of scope for your question.
Hard drives work fine, That is what I use. The only down side is they are fragile and will fail faster than a tape. Make sure you don't put all of your eggs in one basket, and you should be fine.
We used to use tapes, we now use drives, restoration is much faster and we use a device called Teralyte that uses 2 hot swap drives, one permanent and one removable so we still have the ability to take the 2nd drive offsite.
A hybrid system seems to be best-of-breed these days. Use HD backups for your short term (weeks to months) needs, and tapes for off-site and long term archive. If you have fast WAN connections available you can off-site with NAS, but that'll depend on your environment. Keep in mind that backups are part of a business continuity plan decide on the kinds of disasters you want to recover from.