macOS Recovery – Handling Two Recovery Partitions

macosrecovery

Similar, but not a dupe of Time machine restored recovery partition, now I have two

I have a single Recovery partition on my boot drive, even after a recent Time Machine restore. I also intentionally keep 'spares' on other drives, in case of disaster, including an e-drive on the same disk as my Time Machine – so I'm fully prepared in case something ever goes wrong..

However, I've just noticed one drive has two Recovery Partitions.
I'm not sure whether this may cause problems in future; it doesn't seem to be giving me any issues right now, even if I boot to any of the recoveries I can see from the boot chooser, but wondered if it is possible/simple to remove the extra one – or even if it's worth the effort.

It's on a drive with 3 main partitions, Data [Downloads], Boot Camp [MacWin7] & a clone of my regular boot drive [KickClone]

I'm not certain how to even test what OS is on each Recovery, or if it's truly important that it's Sierra.

So, I guess the actual question is …

Is it best to leave it, or to try remove it?
If remove, that would of course lead to a secondary & tertiary, 'which one?' & 'how?'

I wouldn't want to remove it if it's in any way 'dangerous', because I don't have a direct clone backup of the entire drive, only of each partition's contents, so I don't want to have to do a full rebuild of the structure.

/dev/disk3 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *3.0 TB     disk3
   1:                        EFI EFI                     209.7 MB   disk3s1
   2:                  Apple_HFS Downloads               999.3 GB   disk3s2
   3:                 Apple_Boot Recovery HD             784.2 MB   disk3s3
   4:       Microsoft Basic Data MacWin7                 209.1 GB   disk3s4
   5:                  Apple_HFS KickClone               1.8 TB     disk3s5
   6:                 Apple_Boot Recovery HD             1.3 GB     disk3s6

Best Answer

disk3s3 and disk3s6 are both non-default Recovery HDs. I've never seen other sizes than ~650 MB - except after cloning a drive with Carbon Copy Cloner which resulted in a 1.3 GB RecHD partition. 1.3 GB is the size of the uncompressed Base OS X.

To get the system version of the Base OS X do the following:

check with mount that no other volume with the name Recovery HD is mounted, else: unmount it with diskutil umount /Volumes/Recovery\ HD

mount the first RecHD slice r/o:

diskutil mount readOnly /dev/diskXsY #i.e. disk3s3

get the system version of the "outer" Volume:

grep ProductVersion -a2 /Volumes/Recovery\ HD/com.apple.recovery.boot/SystemVersion.plist

get the system version of the inner Base OS X System volume

hdiutil mount /Volumes/Recovery\ HD/com.apple.recovery.boot/BaseSystem.dmg
grep ProductVersion -a2 /Volumes/OS\ X\ Base\ System/System/Library/CoreServices/SystemVersion.plist

Both ProductVersions (outer and inner) should be identical.

Check the content of the volumes:

Recovery HD should contain 3 folders: com.apple.boot.S, com.apple.recovery.boot and System
Base OS X System looks like a normal system volume except /Users is missing and usually invisible folders/links are visible (e.g. /bin or /etc)

Unmount first the Base OS X volume, then the Recovery HD volume.

diskutil umount /Volumes/OS\ X\ Base\ System
diskutil umount /Volumes/Recovery\ HD

Repeat all previous steps with your second Recovery HD:
```
diskutil mount readOnly /dev/disk3s6
...
```

Depending on your results (are both Recovery HDs/Base OS Xs legit regarding their folder structure and the inner & outer ProductVersion) and whether the disk contains a bootable system volume at all (probably KickClone), delete one or both slices. If KickClone contains a bootable system, the (succeeding) Recovery HD should have the same system version (ProductVersion) as KickClone (grep ProductVersion -a2 /Volumes/KickClone/System/Library/CoreServices/SystemVersion.plist).

To delete/remove a Recovery HD simply merge it with the preceding partition:

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This answer applies to Yosemite (OS X 10.10). If you are using El Capitan (OS X 10.11), then you would be better of installing rEFInd in a EFI partition.

In your example, the command would be as shown below.

./install.sh  --alldrivers  --ownhfs  /dev/disk0s5.

I assume disk0s5 has been formatted "Mac OS Extended (Journaled)". I don't think I would use a 17.1 GB partition. The rEFInd partition on my Mac is 134 MB in size.

If you need to write to disk0s5 while booted to Ubuntu, you may have to disable journaling. This usually happens when you need to modify refind.conf.

To turn journaling off, do the following using the Disk Utility application.

Highlight the partition.
Press and hold the "alt/option" key.
From the menu bar select "File->Disable Journaling"
Release the "alt/option" key.
You may have to quit and reopen the Disk Utility to see the change.

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