![](/uploads/1/2/7/3/127381788/960447460.png)
Jump to Why software RAID beats hardware RAID - With software RAID your data can be split across different.We measured performance using a 2 disk mirror. We have been creating RAID software for Mac OS since 1996. Note: If you plan to perform any setup tasks that affect the computer's startup disk (for example, migrating the startup disk or otherwise reusing the startup disk to create new RAID sets or volumes), you need to start up the computer from the installation disc that comes with your computer or from an external disk on which you have installed.
![Raid Raid](/uploads/1/2/7/3/127381788/397762261.png)
While the feature was removed in El Capitan, native software RAID has returned in macOS Sierra. You can access it through Disk Utility, and the graphical interface makes it easy to configure either RAID 1 or RAID 0. Which RAID?RAID stands for Redundant Array of Independent Disks. It’s a protocol that allows users to combine multiple physical hard drives into a single logical data storage structure. This is then seen by the operating system as one drive, despite being made from multiple physical drives.There are a bunch of varieties of RAID. MacOS provides native software support for the most common types: RAID 1 and RAID 0. RAID 1RAID 1, commonly called “mirroring,” use two or more hard drives containing exactly the same data.
In this way, the user is protected against the sudden failure of a disk. It’s important to note that RAID 1 alone isn’t backup. Any user errors or corruptions will instantly copy themselves to both drives.
It’s also only as fast as the slowest hard drive in the RAID set, since write operations must be done simultaneously. RAID 0RAID 0, commonly called “striping,” shares data across both disks without duplication.
You can no redundancy, but you can see a significant increase in read and write speeds. Because RAID 0 includes no duplication, if one drive fails in a RAID 0 array, the whole thing is hosed. This is awesome for applications that require high disk performance but can tolerate a lower level of data integrity, like scientific computing or AV processing. JBODmacOS also offers JBOD, which stands for “Just A Bunch Of Disks.” It’s as prosaic as it sounds. The OS combines two or more drives under one drive name and icon, creating one “logical” disk out of multiple physical disks.
You won’t get any of the features or benefits of RAID 0 or 1. JBOD is essentially a directory of physical hard drives for user convenience. Setting Up RAID in Disk Utility1. Open Disk Utility. Look in /Applications/Utilities or type Disk Utility into Spotlight.2. Click the File menu and choose the menu option labeled RAID Assistant3.
In the next dialog box choose the type of RAID array you’d like to create. Click Next when you’re ready.4. Select the hard drives you want to include in your new RAID array.
You’ll see the same screen here regardless of the kind of array you chose in the last step5. Give your RAID array a clever name. Leave the other options on the default settings. Click Next when you’re done.6. Confirm that you’ve selected the right disks, thought he names might not be too useful. Click “Create” to finalize the array.
This will automatically format the disks and destroy any data on the drives, so make sure you don’t care about that.7. Wait for your array to spin up. This might take a couple minutes, depending on the size of your array and your interface speed.8. The array is now ready for use!In the main Disk Utility window, you should now see your new RAID array in the sidebar. Click on it to see more info about the array.If you have selected RAID 0, the disks you selected will be automatically striped together. If you’ve selected RAID 1, those disks will become mirrors of one another. And if you’ve selected JBOD, all those disks will now appear under a single name and icon within the operating system.
Deleting a RAID ArrayTo break up a RAID array, you’ll need to delete it. This will destroy all the information on the array, so only do this when you’re done. This is especially true of a RAID 0 array, which requires all members to function at all.1.
Open Disk Utility.2. Select your RAID array in the sidebar.3. Click the button labeled Delete RAID4. Confirm your choice in the next dialog box. This will completely erase the disks, so double check.5. Hang tight while the array erases.6. The array will disappear from the sidebar when you’re done.7.
You will need to manually reformat the array’s constituent drives before you can reuse them. Select one of the former array’s disks and click the Erase button in the toolbar. If this button is greyed out, make sure you’ve selected the volume in the sidebar that starts with “RAID Member” rather than the disk itself.7. Select a disk format in the next dialog box.
Typically, this would be automatically filled in, but here you’ll need to make an affirmative selection. Mac OS Extended (Journaled) is or APFS is fine. Click Erase.ConclusionRAID o or RAID 1 can both be configured easily through macOS Sierra’s Disk Utility app. If you want performance and can tolerate low data integrity, go for RAID 0. If you want to protect against disk failure, check out RAID 1. And if you just want to combine a bunch of disks under a single icon, JBOD is for you.You might also like.
We're going to create a striped RAID array to increase the speed at which data can be written to and read from a storage device. Striped arrays provide a speed increase, but they also increase the possibility of failure. A failure of any single drive that makes up a striped array will cause the entire RAID array to fail. There's no magical method to recover data from a failed striped array, which means you should have a very good backup system that you can use to restore data, should a failure of the RAID array occur. Getting Ready. Launch Terminal, located at /Applications/Utilities/. Enter the following command at the prompt in Terminal.
You can copy/paste the command to make the process a bit easier: diskutil list. This will cause Terminal to display all of the drives connected to your Mac, along with the drive identifiers we'll need when creating the RAID array. Your drives will be displayed by the file entry point, usually /dev/disk0 or /dev/disk1.
Each drive will have its individual partitions displayed, along with the size of the partition and the identifier (the name). Terminal should still be open; if not, launch the Terminal app located at /Applications/Utilities/. On page 2, we learned that the identifiers for the drives we want to use are disk2s2 and disk3s2. Your identifiers may be different, so be sure to replace our example identifiers in the command below with the correct ones for your Mac. Warning: The process of creating the RAID 0 array will erase any and all content currently on the drives that will make up the array. If needed.
The command we're going to use is in the following format: Diskutil appleRAID create stripe NameofStripedArray Fileformat DiskIdentifiers. NameofStripedArray is the name of the array that will be shown when mounted on your Mac's desktop. FileFormat is the format that will be used when the striped array is created. For Mac users, this will likely be hfs+. DiskIdentifers is the identifier names we discovered on page 2 using the diskutil list command. Enter the following command at the Terminal prompt. Be sure to change the drive identifiers to match your specific situation, as well as the name you wish to use for the RAID array.
The command below can be copy/pasted into Terminal. An easy method for doing this is to triple-click on one of the words in the command; this will cause the entire command text to be selected. You can then copy/paste the command into Terminal: Diskutil appleRAID create stripe FastFred HFS+ disk2s2 disk3s2. Terminal will display the process of building the array. After a short time, the new RAID array will mount on your desktop and Terminal will display the following text: “Finished RAID operation.”. Launch the Terminal app located at /Applications/Utilities/.
The RAID delete command only requires the RAID name, which is the same as the name of the array when it is mounted on your Mac’s desktop. As such there is no reason to use the diskutil list command as we did on page 2 of this guide. Our example for creating a RAID 0 array resulted in a RAID array named FastFred, were going to use this same example for deleting the array. At the Terminal prompt enter the following, be sure and replace FastFred with the name of your striped RAID that you wish to delete. You can triple-click one of the words in the command to select the entire command line, then copy/paste the command into Terminal: Diskutil AppleRAID delete FastFred. The results of the delete command will be to unmount the RAID 0 array, take the RAID offline, break the RAID into its individual elements.
What does not happen is also important the individual drives that made up the array are not remounted or properly formatted.
![](/uploads/1/2/7/3/127381788/960447460.png)