Checking RAID-1 Mirror Status in OS X El Capitan (now that DiskUtility is toast for RAID)

2015-10-16 • SEND FEEDBACK |
Related: Apple, Apple Core Rot, Apple macOS, RAID, RAID-1, SoftRAID

With the release of OS X El Capitan, Apple has removed RAID functionality and destroyed useful features and added wanton bugs in Disk Utility. Accordingly, MPG recommends that users of DiskUtility RAID turn to SoftRAID.

While MPG strongly recommends SoftRAID for RAID at this point, there are ways to work with RAID at the command line. The most basic of these, particularly useful for checking RAID-1 mirror status, is to list the current status*.

diglloydMP:MPG lloyd$ diskutil appleRAID list
AppleRAID sets (7 found)
... 
===============================================================================
Name:                 MasterClone
Unique ID:            559993DF-7317-43DC-B075-59563FAF6B73
Type:                 Mirror
Status:               Online   <==== no failed disks in mirror = 'Online'
Size:                 1.5 TB (1499387559936 Bytes)
Rebuild:              manual
Device Node:          disk9
-------------------------------------------------------------------------------
#  DevNode   UUID                                  Status     Size
-------------------------------------------------------------------------------
0  disk6s6   B8F6F6D6-7774-4142-866F-0864BFA6F17E  Online     1499387559936
1  disk4s6   0CDF6DA5-7635-4DDC-AAEC-D0C709572C38  Online     1499387559936
===============================================================================

* Creating and manipulating RAID volumes via command line is not for the faint-hearted, particularly when there are many disks present -- one typo and *poof* goes the wrong volume. Use SoftRAID.