Downgrade 10.7.1 (Client) to 10.7
Downgrade is possible, apparently without restriction, but not necessarily OK.
My own case
After using 10.7.1 for a few days, a series of events led me to erase my startup volume then use Recovery OS Time Machine to restore from backup. These events left me without the Recovery HD that is required for FileVault 2.
At that time, version 1.0.8 of the installer was not available.
To regain a Recovery OS:
avoiding my usual account, I used a different account to log in to 10.7.1 (intention: data integrity — avoid my usual home directory at all stages during a downgrade)
I ran version 1.0.4 of the installer on 10.7.1 to install (downgrade to) 10.7
avoiding my usual account, I used a different account to log in to 10.7
I observed an issue affecting a peripheral display — at least one thing not OK
I didn't investigate that issue, didn't seek other issues (intention: spend as little time as possible in a downgraded environment)
I ran Software Update, got 10.7.1 and other updates.
More generally
Data relating to the greatest version of an executable may be incompatible with, or lose integrity with, a lesser version.
Incompatibility or loss of integrity may be acceptable for some types of file (examples: cache files, preference files). For other types (example: application support) integrity may be critical.
For the System version/build over which you wish to reinstall, if Apple provides a matching full installer:
- avoid downgrade — prefer to install a matching system.
Application-specific formats that are designed for export and import
To minimise the risks associated with downgrades, I guess that:
- an archive produced by Address Book in 10.7.1 should be usable without issue in 10.7
- an archive produced by iCal in 10.7.1 should be usable without issue in 10.7
– and so on.
OS X 10.7.4 Core Storage for encryption, ZEVO for ZFS
Example
Objective: one physical disk, five volumes. One of five non-encrypted, one encrypted with a passphrase, three encrypted with a different passphrase.
Starting point:
- /dev/disk2 – a physical disk
- /dev/disk2s2 – a JHFS+ volume to be kept, unprotected
- /dev/disk2s3 – a slice to be destroyed, to be reused with encryption and ZFS.
Hints
Since HFS+ has a single global lock for all metadata updates (held across the I/O) it is highly sensitive to disk latencies. So whilst the mixture of ZFS with JHFS+ on a single disk is possible, for most use cases the file system mixture is not recommended.
This example also makes some use of compression, and of child file systems.
Summary of commands
diskutil coreStorage create pusscats /dev/disk2s3
diskutil coreStorage createVolume 370260EF-D772-4739-BAF6-F4CD6F49A60D jhfs+ Billski 50% -passphrase
diskutil coreStorage createVolume 370260EF-D772-4739-BAF6-F4CD6F49A60D jhfs+ Pickle 100% -passphrase
diskutil unmount disk3 && diskutil unmount disk4
sudo zpool create -O casesensitivity=insensitive -O normalization=formD Billski /dev/disk3
sudo zpool create -O casesensitivity=insensitive -O normalization=formD -O compression=on Pickle /dev/disk4
zfs create Pickle/button
zfs create Pickle/button/nose
sudo chown gjp22 /Volumes/Billski
sudo chown gjp22 /Volumes/Pickle
zpool export Billski && zpool export Pickle
diskutil unmount /Volumes/slice\ two
The output, in Terminal
sh-3.2$ diskutil list disk2
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *8.0 GB disk2
1: EFI 209.7 MB disk2s1
2: Apple_HFS slice two 1.5 GB disk2s2
3: Apple_HFS slice three 6.0 GB disk2s3
sh-3.2$ diskutil coreStorage create pusscats /dev/disk2s3
Started CoreStorage operation
Unmounting disk2s3
Touching partition type on disk2s3
Adding disk2s3 to Logical Volume Group
Creating Core Storage Logical Volume Group
Switching disk2s3 to Core Storage
Waiting for Logical Volume Group to appear
Discovered new Logical Volume Group "370260EF-D772-4739-BAF6-F4CD6F49A60D"
Core Storage LVG UUID: 370260EF-D772-4739-BAF6-F4CD6F49A60D
Finished CoreStorage operation
sh-3.2$ diskutil coreStorage createVolume 370260EF-D772-4739-BAF6-F4CD6F49A60D jhfs+ Billski 50% -passphrase
Passphrase for new volume:
Confirm new passphrase:
Started CoreStorage operation
Waiting for Logical Volume to appear
Formatting file system for Logical Volume
Initialized /dev/rdisk3 as a 3 GB HFS Plus volume with a 8192k journal
Mounting disk
Core Storage LV UUID: 22CF33F0-9EB1-424C-AFFA-FFA45A75A828
Core Storage disk: disk3
Finished CoreStorage operation
sh-3.2$ diskutil coreStorage createVolume 370260EF-D772-4739-BAF6-F4CD6F49A60D jhfs+ Pickle 100% -passphrase
Passphrase for new volume:
Confirm new passphrase:
Started CoreStorage operation
Waiting for Logical Volume to appear
Formatting file system for Logical Volume
Initialized /dev/rdisk4 as a 3 GB HFS Plus volume with a 8192k journal
Mounting disk
Core Storage LV UUID: 500E7D8F-27A3-4704-BF9F-5AE5D6BB6982
Core Storage disk: disk4
Finished CoreStorage operation
sh-3.2$ diskutil unmount disk3 && diskutil unmount disk4
Volume Billski on disk3 unmounted
Volume Pickle on disk4 unmounted
sh-3.2$ sudo zpool create -O casesensitivity=insensitive -O normalization=formD Billski /dev/disk3
Password:
sh-3.2$ sudo zpool create -O casesensitivity=insensitive -O normalization=formD -O compression=on Pickle /dev/disk4
sh-3.2$ zfs create Pickle/button
cannot mount '/Volumes/Pickle/button': failed to create mountpoint
filesystem successfully created, but not mounted
sh-3.2$ zfs create Pickle/button/nose
cannot mount '/Volumes/Pickle/button/nose': failed to create mountpoint
filesystem successfully created, but not mounted
sh-3.2$ sudo chown gjp22 /Volumes/Billski
sh-3.2$ sudo chown gjp22 /Volumes/Pickle
sh-3.2$ zpool export Billski && zpool export Pickle
sh-3.2$ diskutil unmount /Volumes/slice\ two
Volume slice two on disk2s2 unmounted
sh-3.2$ clear
At this point, with all volumes of the physical disk unmounted, you can disconnect the disk. Reconnection should allow use of the child file systems:
sh-3.2$ zfs list
NAME USED AVAIL REFER MOUNTPOINT
Billski 1.04Mi 2.37Gi 684Ki /Volumes/Billski
Pickle 1.87Mi 2.37Gi 472Ki /Volumes/Pickle
Pickle/button 808Ki 2.37Gi 412Ki /Volumes/Pickle/button
Pickle/button/nose 396Ki 2.37Gi 396Ki /Volumes/Pickle/button/nose
sh-3.2$ clear
sh-3.2$ mount | grep /dev/
/dev/disk1 on / (hfs, local, journaled)
/dev/disk0s2 on /Volumes/11E53 (hfs, local, journaled)
/dev/disk2s2 on /Volumes/slice two (hfs, local, nodev, nosuid, journaled, noowners)
/dev/disk4 on /Volumes/Billski (zfs, local, journaled)
/dev/disk6 on /Volumes/Pickle (zfs, local, journaled)
/dev/disk6s1 on /Volumes/Pickle/button (zfs, local, journaled)
/dev/disk6s1s1 on /Volumes/Pickle/button/nose (zfs, local, journaled)
sh-3.2$ clear
sh-3.2$ ls -l /Volumes
total 40
drwxr-xr-x@ 32 root wheel 1156 3 Jun 09:08 11E53
lrwxr-xr-x 1 root admin 1 4 Jun 15:17 11E53-2012-06-03 -> /
drwxr-xr-x 5 root wheel 5 4 Jun 22:27 Billski
drwxr-xr-x 6 root wheel 6 4 Jun 22:33 Pickle
drwxrwxr-x 7 gjp22 staff 306 4 Jun 21:41 slice two
sh-3.2$ clear
sh-3.2$ diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *160.0 GB disk0
1: EFI 209.7 MB disk0s1
2: Apple_HFS 11E53 25.0 GB disk0s2
3: Apple_Boot Recovery HD 650.0 MB disk0s3
4: Apple_CoreStorage 25.0 GB disk0s4
5: Apple_Boot Recovery HD 650.0 MB disk0s5
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS 11E53-2012-06-03 *24.7 GB disk1
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *8.0 GB disk2
1: EFI 209.7 MB disk2s1
2: Apple_HFS slice two 1.5 GB disk2s2
3: Apple_CoreStorage 6.0 GB disk2s3
4: Apple_Boot Boot OS X 134.2 MB disk2s4
/dev/disk3
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.9 GB disk3
1: EFI 209.7 MB disk3s1
2: ZFS 2.6 GB disk3s2
/dev/disk4
#: TYPE NAME SIZE IDENTIFIER
0: zfs_pool_proxy Billski *2.6 GB disk4
/dev/disk5
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.9 GB disk5
1: EFI 209.7 MB disk5s1
2: ZFS 2.6 GB disk5s2
/dev/disk6
#: TYPE NAME SIZE IDENTIFIER
0: zfs_pool_proxy Pickle *2.6 GB disk6
1: zfs_filesystem_proxy button 2.5 GB disk6s1
2: zfs_filesystem_proxy nose 2.5 GB disk6s1s1
sh-3.2$ clear
sh-3.2$ diskutil coreStorage list
CoreStorage logical volume groups (2 found)
|
+-- Logical Volume Group ED97CA61-2077-45CE-9CBB-8AA0A7600CB5
| =========================================================
| Name: b
| Sequence: 1
| Free Space: 0 B (0 B)
| |
| +-< Physical Volume 5C79B2B6-CE01-4F02-9222-2AD898791AC5
| | ----------------------------------------------------
| | Index: 0
| | Disk: disk0s4
| | Status: Online
| | Size: 24999997440 B (25.0 GB)
| |
| +-> Logical Volume Family 7A9C5B98-287F-4F6B-9F9C-9641EFBC16E1
| ----------------------------------------------------------
| Sequence: 11
| Encryption Status: Unlocked
| Encryption Type: AES-XTS
| Encryption Context: Present
| Conversion Status: Complete
| Has Encrypted Extents: Yes
| Conversion Direction: -none-
| |
| +-> Logical Volume 3A130C9E-63AE-4F00-A1C3-E750B1570381
| ---------------------------------------------------
| Disk: disk1
| Status: Online
| Sequence: 5
| Size (Total): 24681226240 B (24.7 GB)
| Size (Converted): -none-
| Revertible: Yes (unlock and decryption required)
| LV Name: 11E53-2012-06-03
| Volume Name: 11E53-2012-06-03
| Content Hint: Apple_HFS
|
+-- Logical Volume Group 370260EF-D772-4739-BAF6-F4CD6F49A60D
=========================================================
Name: pusscats
Sequence: 1
Free Space: 0 B (0 B)
|
+-< Physical Volume F64F6909-25BF-4638-8647-CD058D60968B
| ----------------------------------------------------
| Index: 0
| Disk: disk2s3
| Status: Online
| Size: 6020829184 B (6.0 GB)
|
+-> Logical Volume Family 4D42970B-FAB7-4EFE-B120-2057A9A7A7E5
| ----------------------------------------------------------
| Sequence: 2
| Encryption Status: Unlocked
| Encryption Type: AES-XTS
| Encryption Context: Present
| Conversion Status: NoConversion
| Has Encrypted Extents: Yes
| Conversion Direction: -none-
| |
| +-> Logical Volume 22CF33F0-9EB1-424C-AFFA-FFA45A75A828
| ---------------------------------------------------
| Disk: disk3
| Status: Online
| Sequence: 2
| Size (Total): 2934915072 B (2.9 GB)
| Size (Converted): -none-
| Revertible: No
| LV Name: Billski
| Content Hint: Apple_HFS
|
+-> Logical Volume Family 3A009EF4-4B3D-4BC8-8B47-EFE88B2BA12A
----------------------------------------------------------
Sequence: 2
Encryption Status: Unlocked
Encryption Type: AES-XTS
Encryption Context: Present
Conversion Status: NoConversion
Has Encrypted Extents: Yes
Conversion Direction: -none-
|
+-> Logical Volume 500E7D8F-27A3-4704-BF9F-5AE5D6BB6982
---------------------------------------------------
Disk: disk5
Status: Online
Sequence: 2
Size (Total): 2934910976 B (2.9 GB)
Size (Converted): -none-
Revertible: No
LV Name: Pickle
Content Hint: Apple_HFS
sh-3.2$ clear
sh-3.2$ zpool status
pool: Billski
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
Billski ONLINE 0 0 0
GPTE_7CBD336C-568A-41AE-8E61-291CBD8EF783 ONLINE 0 0 0 at disk3s2
errors: No known data errors
pool: Pickle
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
Pickle ONLINE 0 0 0
GPTE_25BF8159-FB8D-4589-B52A-184F6675176E ONLINE 0 0 0 at disk5s2
errors: No known data errors
sh-3.2$
The end result, in Finder
Known issues
In CoreStorage world the content hint Apple_HFS will be not true for the ZFS end result. I have asked Apple to allow a more suitable hint.
At unlock time, the system may appear to reject the passphrase (maybe because of the content hint mismatch). When rejection appears:
- wait
- the unlocked volume (and any child file systems) should mount
- escape from the password dialogue.
If you wish, use Keychain Access to add to a keychain the passphrase for the UUID of a Core Storage logical volume.
Mountain Lion no longer supports diskutil eraseDisk placement of partition maps on Core Storage logical volumes –
gpes3e-gjp4:~ gjp22$ diskutil list /dev/disk4 && diskutil list /dev/disk5
/dev/disk4
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *8.0 GB disk4
1: EFI 209.7 MB disk4s1
2: Apple_CoreStorage test 7.7 GB disk4s2
3: Apple_Boot Boot OS X 134.2 MB disk4s3
/dev/disk5
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS test *7.3 GB disk5
gpes3e-gjp4:~ gjp22$ diskutil unmount /dev/disk5
Volume test on disk5 unmounted
gpes3e-gjp4:~ gjp22$ sudo zpool create -O casesensitivity=insensitive -O normalization=formD Billski /dev/disk5
Unable to begin erase operation: Placing a partition map on a Core Storage logical volume is not supported (-69671)
diskutil eraseDisk failed, exit status 1
gpes3e-gjp4:~ gjp22$ sw_vers
ProductName: Mac OS X
ProductVersion: 10.8.5
BuildVersion: 12F37
gpes3e-gjp4:~ gjp22$
– thanks to mgrosman for the alert.
Repairs
Considering Apple's design of Core Storage to work primarily with content hint Apple_HFS, and the bugs in fsck_cs:
- I don't know whether 'forcing' alternative types (
ZFS, zfs_pool_proxy, zfs_filesystem_proxy and so on) might impair the ability of fsck_cs to effect repairs in case of difficulty.
Proceed with caution.
Best Answer
My working theory is that there are no meaningful differences in actions performed under the app as opposed to the DMG.
One could argue at a low level that the difference is that invoking the
Install OS X Mountain Lion.appbundle loads app and UI frameworks that simply mounting a DMG does not, but that's not exactly the intent of your question I'm sure.Any meaningful installer-level actions should be identical in either medium, since the majority of the resources are in the DMG, and the DMG is in the app. The app must mount the disk image in order to get at the necessary assets.