[andreas_g4]

To protect me from drive failures, I want to use a Level 0 RAID on my home iMac. I don't want the recover-feature of Time Machine, I only care for the redundancy (I could still add TM to my array).

The problem is, 3.5 inch drives are all pretty noisy, whereas 2.5 inch drives are nearly silent (good ones). So I'm basically looking for a 2.5 inch RAID with USB 2.0 and both FireWire flavors.

Is there anything like that? I thought I'd seen one of these somewhere, but can't find any online. Any help?

[OreoCookie]

A RAID0 does not give you redundancy, that's RAID level 1. You can use OS X' software RAID to do just that: get enclosures of choice for your harddrives, plug them in and create the RAID1.

[andreas_g4]

You are right I mixed up the RAID levels. But I'm aware of the software RAID features of OS X, I'm looking for the enclosure I described…

[mduell]

There are plenty of dual-drive hardware RAID (0/1) enclosures with USB and Firewire out there, but most are for 3.5" drives and most 2.5" to 3.5" drive converters have the wrong power plug to work in them.

The difference in noise between 3.5" drives and 2.5" drives is only about 4 dB, which is barely over the threshold for humans to be able to tell the difference. If you don't find a dual drive 2.5" enclosure, I'd suggest you consider low speed 3.5" drives instead.

[Simon]

+4dB means it's more than twice as loud actually. Perceived volume and actual acoustic power are not the same thing, but you can be certain that anybody with average hearing can distinguish +4dB as long as both noises are above the auditory threshold and below full saturation. And since we can usually hear drives, that is the case.

So as we know from regular experience we can indeed hear a difference between 2.5" and 3.5" drives - especially during reads/writes. If you cannot find such a 2.5" RAID enclosure with FW and USB, I'd suggest you look into the damping of the case. If you get a really good 3.5" case it might just make up for the additional noise of the drives by improved attenuation. There's a company that specializes in noise-reduction enclosures, but I forgot the name. Maybe somebody else here can point to them.

[mduell]

Originally Posted by Simon 

+4dB means it's more than twice as loud actually. Perceived volume and actual acoustic power are not the same thing, but you can be certain that anybody with average hearing can distinguish +4dB as long as both noises are above the auditory threshold and below full saturation. And since we can usually hear drives, that is the case.

Yay, we agree. Thread over.

[OreoCookie]

There is another unit that takes the `perceived' loudness into account, Sone. I haven't seen any company that measures in Sone, though, only a few tests do that.