I have an older server with two hard drives in a raid and a tape backup. The data on the drive that needs to be backed up is more than the tape will hold. I am debating between getting an external hard drive and a network attached storage device to back up the data. For security I like the idea of the NAS being in a different part of our building but I don't know if this make is a better choice than an external drive. No one needs to be able to access the data on the backup device except in the event of server failure. I have tried to compare them on my own but I have been overwhelmed with the online information.
 
In your experience, what is the easiest and most efficient hardware device to use in a nightly server backup?

Is it automated?  Or does someone perform this task?  Can you purchase larger tapes or are you already at capacity?  I would hate to see you have to replace an already functioning system if you can go for larger capacity tapes.

 
The tapes are changed by an employee. The tapes we have are the largest that the drive will accept so the tapes are no longer an option. One reason I was looking into an external drive or NAS is that I would like the backup to be automated.

Are you using compression on the tapes? How much data are we talking about?
 
DLT or LTO?
 
(I know you said they aren't big enough, but i figure its worth asking.)

I don't know much about the tapes, I am coming into this second hand. I was just given the task of finding a better backup solution.  
 
The amount of data to back up is +/- 50 gigabytes.

How would you automate it?  If your going through a vendor they usually provide the backup medium in the solution.  If you are designing this yourself, there's a few ways.  You could script a copy operation to another location if the file isn't actively in use at the time.  There are just too many factors.

Hmm. Find out more about the tapes. Your employer may appreciate your money saving research.
 
Some DLT tapes can store up to 800GB compressed.
Even older tapes will still store 80Gb compressed.
If you are running a DLT1 (40GB native, 80GB compressed) all you may have to do is enable compression on the backup program.
 
I am going this route because tape back-ups really are the most effective solution. They are used in enterprises all over the world. A company I used to work for would back up more than 10TB a day, all to tapes.
 
The key is to develop a good strategy for rotating tapes, and doing a daily incremental/differential, with a weekly full, then taking the weekly fulls offsite.
 
(what back-up application is being used?)

The tapes we have only hold 2gb or 4 compressed and are the biggest we could find for our drive. The tape drive is not working correctly and ejects the tape as soon as it is inserted.  
 
We like the idea of not having to change the tapes and having the backup scheduled and recorded on a hard drive. We have had issues making sure the night shift rotate tapes and use the correct tapes.
 
I am still trying to find out what backup program was being used.

As mentioned above, Tape Backup is really the way to go.
 
While you could backup to a another HDD, you really will not have the history. you need.
 
You should get a good tape system and good backup software.
 
Clearly it's more money, but if your data is ever really lost your company is in more trouble.
 
Example - Let's say the data on your Server HDD gets corrupted/damaged.  But it's done in a manner that it may take you a week or two to realize it.
Soon everything on your "Backup" NAS device has been overwritten.
 
There is no recovery at this point and you are hosed.
 
Get tape backup.

^^  Yup, if this is for a production corporate environment that is a good statement.  You need at least 30 days worth of backups available.

You can do a series of backups on a NAS device (the +/- 50 GB is nothing compared to modern 500-1000GB drives if he did a weekly full with daily incrementals they could have a long history (months-years depending on the NAS drive).
 
That said if the NAS fails there are no backups, if there is a fire there are no backups.  Tapes can have a set stored on site and others off site.  Of course drives can be swapped out too, depending on the type of NAS and the backup software.
 
You could even use Iomega 120 GB Rev drives.

One word ....FreeNAS..........
http://www.freenas.org/
 
Works really well.....No complaints and easy to set-up!