I'm thinking about replacing my single 500GB data drive with a 1TB drive. Since I have folder duplication turned on, is this really as simple as shutting down the EX485, pulling the 500GB drive, installing the 1TB drive, and booting back up?

I should have added the following steps to my question above: Remove the current 500MB drive from the pool before shutting down the EX485 and pulling the drive. Then add the new 1TB drive to the pool after inserting it and re-booting the EX485

I would say (no) it's not that simple.
It should be that simple but it's not, you should be able to plugin the new drive, reboot and run the recovery dvd, but most of the time it doesn't work. At least for me.This is your choices:
Complete Reset:
1) you backup all your data and format all the drives ( I use a usb to harddive docking station to do this, it will come in handy later) and run check disk on all the drives to make sure they are all good.
2) put the new 1tb system drive in the bottom slot (bottom slot is for the system drive) and leave the other drives out for now.
3) connect the server directly to a desktop or laptop running win xp 32 bit using cat5, no switch or router. and run the recovery dvd, select (reset to factory) and take your time, when it wants to do something, wait 5 mins. if it wants to reboot, wait 5 mins. lots of waiting is good.
4) when done you can add the harddrives back to the pool, but I would have (1) 2tb drive not added to the pool to backup your shares and then start coping your data back, but always have a backup of your data.

Recovery:
1) put the new disk in the bottom slot (I would still format and check it to make sure it's good) the directly connected as above run the recovery dvd and pick recovery, you would do this with the other drives in so it could keep your data.

I have tried the recovery twice and it failed bot times and I almost lost my data, so what ever you do, backup the data you can't lose.

Sorry to sound jaded, but I found resets to be the best.
Goodluck

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The OP asked about replacing his data drive, not system drive.

If you are replacing a data drive, then yes, simply Remove it via the Server Console, let the removal process complete, then physically remove the drive. If you have a free slot you can add the new data drive before removing the old. You don't even have to reboot.

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Alex Kuretz
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Thanks Alex. I was hoping it was that simple. Didn't know these were hot swappable. Good thing to know.

Now to figure out which drive to buy. Been reading some of the threads here and will probably go with a WD with the jumpers to take care of the Advanced Format problem, as that seems like an easy solution. Now to decide between a standard drive and one of the "green" drives (with auto-park turned off). Decisions, decisions!