Are the two drives setup as one plus a mirror (RAID Level 1)? I purchased a NAS a few years ago and set it up originally as RAID 5 with four 500gb disks giving me (N-1) or 1.5TB of redundant storage. It is great but my two design guys have issues with it, and so do I because of Photoshop. So now it's just a network backup drive.
For each workstation now we have a total of 4 drives and have 2 paired up for mirroring so C is OS and D is documents/files and then an external USB 2.0 + eSATA drives which are at least 1TB. All the working files we keep on the local drive and have it backup to the external. We barely use the NAS now. I used to also have Quickbooks files on the NAS and that just doesn't work. It now has it's own
Windows server where that file sits and is shared using the QB server setup.
So...
NAS Pros - network share that everyone can access
faster 100mb to 1GB network connections
redundant using RAID 1-5 or higher on the newer models
NAS Cons - network share that everyone can access
- expensive 500-900 for the case plus the cost of your drives
External Pros - using eSata the data access speed is the same as a local drive
- low cost: 1TB 7200rpm drive plus case is under $150
External Cons - requires a little more work to setup as a network share and may be offline if that PC is down or the drive is not attached.
- single point of failure. if the drive fails you have lost data (there are now 2 disk eSata cases which support RAID 1 mirroring)
that's what I can think of at the moment. I'm about to build a new graphics workstation to replace a 4 year old one. It will have Win7 x64, 16gb ram, 4 drives setup as two pairs RAID 1, and an external drive for backup or pushing off older working files.
What is your primary need or purpose for the NAS or external drive?