I recently purchased a few Western Digital Red hard disks, and I am utterly amazed at how quiet they are. No grunting noises when seeking, no buzzing from vibration, nothing but a quiet hum. The disks are no louder than the fan on the RAID enclosure I mounted them in. I've historically gone with Seagate instead of WD, and I've been fairly satisfied with those drives, but the Seagate drives in my home server make all kinds of grunty noises when in active use. In fact, that's the main reason my server lives in a closet: the fans are pretty darn quiet, but the disks make obnoxious noises at random intervals. If a Raspberry Pi proves sufficient to act as a media center PC, I think I'll just hook up the RAID enclosure to my current media center and make that the home server. If I can get away with not using the fan on that machine (not using its GPU anymore should keep it cooler), then it should be so quiet that I can put it somewhere more convenient than a closet. WIN!
Performance is good, too. See the bonnie++ output below (using btrfs on top of hardware RAID 5 via USB 3). Performance with XFS is similar.
Version 1.96 ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP jekyll 15864M 502 98 122763 19 35330 12 2763 84 171190 29 123.0 6 Latency 52353us 200ms 277ms 60373us 210ms 25013ms Version 1.96 ------Sequential Create------ --------Random Create-------- jekyll -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 17863 27 +++++ +++ 26661 66 27059 46 +++++ +++ 18532 61 Latency 305us 1224us 2712us 330us 47us 1420us
In short, I absolutely recommend WD Red hard disks for NAS-type devices, especially if quiet operation is important. Totally worth the extra money.
Update (2015-09-12): I'm still using those disks, and I still like them.