Creating a RAID 1 with two external drives.

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Creating a RAID 1 with two external drives.

Hello,

Recently, I decided it would be a good idea to create "back up" system to protect the 2 TBs of movie, music, photos, etc. I've created over 15 years. I've been looking at RAID 1 systems so that if a external hard dive with this material fails mechanically, I'll have another drive with everything on it I want to protect.

Yes. I know this is not a true back up and I do not care about that. What I want it protection against drive failure. (Personally, I have never had a drive of any kind fail, but I am not about to tempt fate with all this work.)

I've been looking at WD duo drives which can be set up to mirror figuring I can clone my current external onto one drive and have it mirror to the other for extra redundancy. (I really don't want to lose my media if you can't tell.)

However, while on Amazon, it occurred to me I might be able to buy a couple Seagate 5 TB drives for half the price to do the same thing by daisy chaining them with a USB tree.

Again, this is all about redundancy for me. I've never thrown or destroyed anything I've never intended to destroy or throw away. After closing my currently full 2 TB external onto the new set up (two 5 TB drives- cloning one and mirroring to the other), I figured I would use the current drive as a time machine.

Thoughts? Does it sound feasible? Can two external drives be set up as a RAID 1 to protect redundancy?

Posted on Aug 22, 2016 2:22 AM

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Answer 1

Corrie84

Community Specialist

Aug 22, 2016 2:45 PM in response to Arcticfoxxx

Hi Arcticfoxxx,

I see that you're looking to set up a mirrored RAID set (also called "RAID 1") with your two external drives to protect against hardware failure. I know how important it is to make sure digital content is backed up and safe, so I'm happy to provide some assistance.

Take a look at the following resource that has information on how to create a RAID set with Disk Utility:

Disk Utility (Yosemite): Create a RAID set

Create a mirrored RAID set

Protect your data against hardware failure with a mirrored RAID set (also called “RAID 1”). When you create a mirrored RAID set, your data is written to multiple disks so the information is stored redundantly.

You can’t create a RAID set on your startup disk; you must first start up your computer from another disk.

Select one of the disks that you want in the set, then click RAID.

Click Add , then enter a name for the RAID set.

Click the Format pop-up menu, then choose a format.

Click the RAID Type pop-up menu, then choose Mirrored RAID Set.

Drag the disks you want to add to the set to the list on the right.

For each disk, select it, then choose its type from the RAID Type pop-up menu.

To use the disk as a mirror at all times, choose RAID Slice.

To use the disk as a mirror only when another disk fails, choose Spare. A disk can be a spare in only one RAID set.

If a disk in the set fails and you have no spares, you must add a new disk to the RAID set in Disk Utility to return to the original number of disks.

To rebuild disks automatically when they’re disconnected and then reconnected, click the Options button, select RAID Mirror AutoRebuild, then click OK.

Click Create.

Take care!

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