We recently upgraded the drives in a few of our servers to new WD RE4-GP 2TB drives. Initially these drives worked really well, but after a little time, we noticed that the RAID controller they were connected to (an ARECA based controller) was reporting a significantly higher number of "read timeout" errors for these drives (a few per day, rather than "every now and then" as for all other drives).
Looking around, we found other reports of problems with these drives and RAID controllers, although ours weren't as serious as the other reports, drives weren't "dropping" out of our arrays, just more read timeouts. In one of the comments posted on that blog, a user notes there's an upgraded firmware for the WD drives that helped him.
Searching around, I also found out about the firmware update in the knowledge base on the 3ware site, from 04.05G04 to 04.05G05. It seems they are also recommending it for compatibility with their RAID controllers, and include a copy of the new firmware there (with all the usual disclaimers of course). Unfortunately the process to upgrade the firmware requires attaching the drive directly to a motherboard SATA controller and running a DOS only utility. To do that for the 24 drives would be a slow and annoying process.
Fortunately it turns out that modern SATA drives now have a standard process for upgrading the firmware, so it's actually possible for this to be done via the RAID controller rather than requiring a custom upgrade program. With some help from our vendor (thanks Hao Zhang at e23 Inc) and ARECA, they were able to build the new firmware file into a format suitable for upload to their RAID controllers. So we did that, rebooted the unit, and a few minutes later, all the drives in the unit had been upgraded to the newer 04.05G05 firmware. Nice and quick and easy. (Sorry, we can't distribute this file, so please don't ask us. Contact your vendor to get it if you need it)
Since then, there's been no read timeout errors reported by any of the drives, and they've continued to work really well.
So if you're using the WD RE4-GP 2TB drives and having problems, make sure you upgrade them to the latest firmware version.