Raid 1 with slightly different drives?

[ouch]

I'm in the process of rebuilding/enhancing my home file server/media server.

It's currently got a single 3yr old WD Caviar green 2TB drive in it. I want to create a Raid 1 arrangement to ensure I've got some redundancy. As it's a fairly old drive, finding an exact replacement is difficult, and also potentially expensive.

Would I be heading for a ton of grief if I put it alongside a newer 2TB drive? Comparing the current line up of WD caviar greens (WD20-EzRX) against mine (WD20-EADS) shows the newer drives are sata 2 rather than sata 1, and have 64mb cache, rather than 32. Are these differences likely to be noticeable or cause problems? I guess one scenario is that the raid controller throttles the (supposedly superior) performance of the newer, quicker drive to match that of the older one, is this the likely outcome?
Would I be better in putting it aside as USB based 2nd line backup, and getting a pair of barracudas or some other 7200rpm drives?

There'll be a 3rd smaller drive hosting the OS and non served data.

If it makes any difference, they'll be run off a Startech 2-port PCI-E add in card, and the system is running Debian..

 

[anti-duck]

You can use different drives with a RAID 1 array, but remember that the capacity is only going to be as large as the smallest drive in the array and as fast as the slowest drive in the array. Did you mean that your current drive is SATA 2 and the one you're looking at is SATA 3? A SATA 3 mechanical HDD won't saturate the bandwidth of a SATA 2 port so you're fine there.

 

[ss202sl]

The other thing you may run into is getting the raid set up. Most raid configurations will wipe the data from the drives as it formats the drives for use in the raid. Your best bet may be to just get a newer(faster - WD Black) drive, copy the contents of the old drive to the new drive.

 

[ouch]

I was going to use a same-size drive anyway, the old drive is sata 2, the current ones are 3.

TBH WD have a bit of a gap in the market for fast budget 2Tb drives, so if I did go for a fresh pair, I'd probably go with a 2x 2Tb Barracudas. I've got other drives (albeit multiple, smaller ones) I can back-up onto when I set up the array, so that's not a massive problem.