Creating a Software RAID in Mac OS X El Capitan

While this was a simple task on earlier Mac OS X versions, you can’t find an option to create a RAID in newer versions, you have to use terminal to create it. Fortunately it is very simple and harmless, as long as you take your time to carefully check which drives you are including in the command.

Unfortunately I did this before I took a screenshot of it, but it is so simple that the command is enough. But as I mentioned above, DO make sure that you have the drive names correct before issuing the command. You can use Disk Utility, or from terminal write:

diskutil list

This will list all your attached drives.

Creating a RAID in El Capitan (or later): 

When you have found all the drives you want to put in the RAID, the following command is all you need:

diskutil appleraid create stripe Data JHFS+ disk1 disk2 disk3

 

You need the first part, ‘diskutil appleraid create’, then you specify which type of RAID you want. I wanted stripe (RAID0). After that you specify a name (diskID) for the RAID (Data) and file system (JHFS+, Mac default). After that you list all the drives you want to use, and hit enter.

You can write the following command to see the details for your RAID

diskutil listRAID

I want to stress that RAID0 offers NO redundancy, and you will lose all data on all RAID members should one drive fail. It is speed and space only. I’m using this on 3x 120GB SSD’s I have to save money to get 360GB storage, and a fast drive. I have Time Machine configured with full backup, should one of them fail. Do the same if you are using a striped RAID. I would also like to mention that any mirrored RAID really isn’t an alternative for a backup, RAID is for redundancy, and you will still need another backup. I don’t mind having to copy back <360GB from backup, should my RAID fail, take this into consideration for your setup.

Deleting a RAID:

You might want to delete for reconfiguration later, this is really simple, but be sure before issuing the command:

diskutil appleraid delete <diskID>

You can find the diskID with:

diskutil list
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