How to Rebuild Software RAID 10 in Mountain Lion – Command Line

Posted: February 27th, 2014 | Author: | Filed under: Mac OS X, Mac OS X Server, RAID | No Comments »

Removal

First, replace the disk 😉

Open a terminal session on affected system and run
diskutil appleRAID list
find the UUID for the affected drive and the UUID for theRAID set. Then fill in the blanks below:
sudo diskutil appleRAID remove <drive UUID> <RAID UUID>
For example:
sudo diskutil appleRAID remove EEDD0AD6-C448-48F7-A766-001C65338E99 7010C337-829C-4F08-B6A4-1C8A9E943CBD
Our RAID 10 now only has three disks attached.

Rebuild

First we need to identify the spare disk waiting for us in the system. Use diskutil list to do this. Here’s some example output. See if you can spot the disk that is not like the others.

# diskutil list

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *119.9 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:                  Apple_HFS ServerHD                118.9 GB   disk0s2
   3:                 Apple_Boot Recovery HD             784.2 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk1
   1:                        EFI                         209.7 MB   disk1s1
   2:                 Apple_RAID                         2.0 TB     disk1s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk1s3
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk2
   1:                        EFI                         209.7 MB   disk2s1
   2:                 Apple_RAID                         2.0 TB     disk2s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk2s3
/dev/disk3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk3
   1:                        EFI                         209.7 MB   disk3s1
   2:                 Apple_RAID                         2.0 TB     disk3s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk3s3
/dev/disk4
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                                                   *2.0 TB     disk4
/dev/disk5
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Storage                *4.0 TB     disk5
thuja:~ pwladmin$

 

We can see in this list that disk4 has no partition maps and thus is the new disk. We can now add this disk into our degraded raid with:
sudo diskutil appleRAID add member <NewMemberDeviceName> <RAID UUID>
for example
sudo diskutil appleRAID add member disk4 7010C337-829C-4F08-B6A4-1C8A9E943CBD
Your disk is now part of the raid set. If you use diskutil appleRAID list you’ll be able to check the progress of the rebuild.

===============================================================================
Name: Thuja RAID A
Unique ID: 920F03EB-DE44-49AA-9934-0EF53EF032D1
Type: Mirror
Status: Online
Size: 2.0 TB (2000054910976 Bytes)
Rebuild: manual
Device Node: -
-------------------------------------------------------------------------------
# DevNode UUID Status Size
-------------------------------------------------------------------------------
0 disk1s2 D4BCB349-3255-473B-B586-EAF066C5BD6D Online 2000054910976
1 disk3s2 E01DB36B-CDC4-458C-AC07-507433DCB481 Online 2000054910976
===============================================================================
===============================================================================
Name: Thuja Stripe RAID
Unique ID: 9D9FEE5F-5F04-4051-A0AB-A985DFFAF2A0
Type: Stripe
Status: Online
Size: 4.0 TB (4000109559808 Bytes)
Rebuild: manual
Device Node: disk5
-------------------------------------------------------------------------------
# DevNode UUID Status Size
-------------------------------------------------------------------------------
0 -none- 920F03EB-DE44-49AA-9934-0EF53EF032D1 Online 2000054779904
1 -none- 7010C337-829C-4F08-B6A4-1C8A9E943CBD Online 2000054779904
===============================================================================
===============================================================================
Name: Thuja RAID B
Unique ID: 7010C337-829C-4F08-B6A4-1C8A9E943CBD
Type: Mirror
Status: Degraded
Size: 2.0 TB (2000054910976 Bytes)
Rebuild: manual
Device Node: -
-------------------------------------------------------------------------------
# DevNode UUID Status Size
-------------------------------------------------------------------------------
0 disk2s2 13AFF0CD-77FB-4E14-9A89-A09C01ACA4C4 Online 2000054910976
1 disk4s2 EAE79161-3729-41FB-81A1-97CE878C1E31 1% (Rebuilding)2000054910976
===============================================================================

 



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