Question about RAID on external drives

[Luddite]

I have a noob question(s) about RAID on external storage drives.

I'm planning to get a 2 bay external enclosure, something like this: https://eshop.macsales.com/item/Other World Computing/MEMDC2KIT/

1. Can I start with one drive, and simply add another later? Will the first drive automatically send the files to the newly added second drive? Or do I have to use a separate dock or something to transfer the data between them?

2. Can I switch between RAID 1 and RAID 0 on the same drives? For instance, if I have the drives set on RAID 1 and I have a large file I'd like to back up faster by using RAID 0, can I switch? Or can the drives only be set to one or the other RAID type on the same drives.

Thanks!

 

[ArisVer]

I believe the answer is no to both questions.

To build a RAID 0 or RAID 1 array you need to setup the array from the beginning using at least two drives.

There is no switching between RAID 0 or 1 as far as I know.

You better do some more reading about RAID before you continue your work.

 

[ch33zw1z]

Answer 1: RAID0, nope.....RAID 1, maybe, depends on the enclosure

Answer 2: nope.

 

[Luddite]

Thanks, I was sort of afraid of that.

1. So, to add a second drive I would need to reformat the first drive and start them both afresh, is this correct?

2. I would need to pick a RAID setting beforehand and stick with that setting.

 

[ch33zw1z]

Thanks, I was sort of afraid of that.

1. So, to add a second drive I would need to reformat the first drive and start them both afresh, is this correct?

2. I would need to pick a RAID setting beforehand and stick with that setting.

1. Pretty much. Raid 1, you might be able to add the second drive later since it's two partitions in a mirror. Raid 0, no, since raid 0 is stripped across two drives and creates one volume.

2. That's recommended and preferred

Also, raid is NOT a backup. Get a separate disk equal to the logical volume size and backup the array to that.