Does RAID1 require identical hard drives?

[wito]

Hi,

I've just bought a Necus N2100 (mostly because from what I've read it's a very open system). I want to operate it in the RAID1 mode. Unfortunately, I didn't find much information on whether this requires compeletely identical hard drives (same model) or just hard drives of identical size. The reason for this question is that in case RAID1 requires fully identical hard drives I guess it makes sense to buy a spare disk as well - just in case a disk fails and I cannot obtain an identical replacement immediately.

The second question I was wondering about is, whether the RAID functionality is provided by hardware or by the firmware (as software RAID). The reason for this question is that if I replace the firmware with Linux, would I lose the RAID functionality or not (I know that Linux would offer me software RAID in this case).

Thanks,
Stephan

[dbridges]

Someone correct me if i'm wrong but Raid 1 on the n2100 is a software raid running as part of the linux os.

You can use non identical drives but you will only get the capacity of the smallest drive.

Also the non matching drives will generally have mixed history with respect to usage and one will be a lot closer to failure than the other.

You're doing raid 1 for data security reasons so it would make sense to buy two identical drives because then you know that both drives have an identical usage history.

Dont worry about buying a spare drive because if you buy two drives and one of them fails completely after 6 months you can be pretty sure that the other one wont be far behind it.

When one drive fails you get all of your data off the other one as quick as possible and install two new drives then use the leftover drive for some non critical purpose elsewhere.

Sure the leftover drive may function well for years afterwards but is the risk worth it?

[wito]

Thank you very much for your reply! It helped a lot.