Mac – Repair Time Machine sparsebundle that will no longer mount

sparsebundletime-machine

I messed up my Time Machine backup in some way. I'm no longer able to mount the sparsebundle file as I get an error stating that there are no mountable filesystems.

I used the hdiutil command to attach the sparsebundle file:

hdiutil attach -nomount -readwrite flattop.sparsebundle

which resulted in the following /dev/ devices:

/dev/disk2              Apple_partition_scheme
/dev/disk2s1            Apple_partition_map
/dev/disk2s2            Apple_HFSX

Afterwards I ran the fsch_hfs command to check the main volume (/dev/disk2s2):

fsck_hfs -drf /dev/disk2s2

This resulted in a notice that the Time Machine Backups volume is corrupt and needed to be repaired:

Unable to open block device /dev/disk2s2: Permission deniedjournal_replay(/dev/disk2s2) returned 13
** /dev/rdisk2s2 (NO WRITE)
    Using cacheBlockSize=32K cacheTotalBlock=32768 cacheSize=1048576K.
   Executing fsck_hfs (version diskdev_cmds-540.1~34).
Non-empty journal:  start = 66310144, end = 94912512
   Journal need to be replayed but volume is read-only
** Checking Journaled HFS Plus volume.
** Detected a case-sensitive volume.
   The volume name is Time Machine Backups
** Checking extents overflow file.
   Unused node is not erased (node = 3568)
   Unused node is not erased (node = 3574)
   Unused node is not erased (node = 3575)
** Checking catalog file.
** The volume Time Machine Backups was found corrupt and needs to be repaired.
    volume type is pure HFS+ 
    primary MDB is at block 0 0x00 
    alternate MDB is at block 0 0x00 
    primary VHB is at block 2 0x02 
    alternate VHB is at block 2865568974 0xaacd1cce 
    sector size = 512 0x200 
    VolumeObject flags = 0x07 
    total sectors for volume = 2865568976 0xaacd1cd0 
    total sectors for embedded volume = 0 0x00

As you can see there is also an error saying "Unable to open block device /dev/disk2s2: Permission deniedjournal_replay(/dev/disk2s2) returned 13".

I thought this might be due to not running the fsck_hfs command as a su, so I tried it with sudo but this had the same result.

My sparsebundle file is on a Synology DS408 NAS and has been running without a problem for about 2 years now 🙁

Anyone an idea how to take this further?

Kind regards,
Niels R.

UPDATE: As I suspected while writing this question I probably have a problem with read/write permissions. I now see the volume appearing in the Disk Utility and when I click on "Verify" I get the following output:

Verifying volume “Time Machine Backups”
Checking file systemJournal need to be replayed but volume is read-only
Checking Journaled HFS Plus volume.
Detected a case-sensitive volume.
Checking extents overflow file.
Unused node is not erased (node = 3568)
Checking catalog file.
Keys out of order
The volume Time Machine Backups was found corrupt and needs to be repaired.
Error: This disk needs to be repaired. Click Repair Disk.

Can I simply chmod the sparsebundle file to set the right permissions?

Best Answer

I have a write up on how to try and repair NAS-based sparsebundle errors on my blog. In summary:

hdiutil attach -nomount -noverify -noautofsck /Volumes/{name of your disk}/{name of}.sparsebundle

You will then see something like
```
/dev/diskx Apple_partition_scheme
/dev/diskxs1 Apple_partition_map
/dev/diskxs2 Apple_HFSX
```
Where x is the disk id for the external disk. x might be 2, 3, 4 or higher. You are interested in the one labeled Apple_HFSX or Apple_HFS.
fsck_hfs -drfy /dev/diskxs2 using whatever relevant device was located in Step 1.

Hopefully, you will eventually see

The Volume was repaired successfully
hdiutil detach /dev/diskxs2

However, since OS X 10.6.3, Time Machine will refuse to write to a destination volume that fails its verification. Even if the process above succeeds in recovering the backup, you may still need to remove the black marks that Time Machine wrote when it failed verification.

Unlock the sparsebundle

chflags -R nouchg /Volumes/{name of your disk}/{name of}.sparsebundle

Move it back to its original location

mv /Volumes/{name of your disk}/{name of}_YYYY-MM-DD.sparsebundle /Volumes/{name of your disk}/{name of}.sparsebundle

At the top level directory of the sparsebundle, edit the file com.apple.TimeMachine.MachineID.plist.

Remove

<key>RecoveryBackupDeclinedDate</key>
<date>{whatever-the-date}</date>

Change

<key>VerificationState</key>
<integer>2</integer>

<key>VerificationState</key>
<integer>0</integer>

Related Solutions

MacOS – How to save data from a time machine backup that has gone bad

I am simply going for an answer with this because I believe it is the only one.

First of all don't use Finder. If you do, don't copy it all because Finder does not understand what a hard link is.

If you would like to keep the data in sort of the same structure you can use rsync with a version number greater 3. Not the version supplied by Apple. With that you would be able to copy the volume including hardlinks while preserving xattrs and permissions. With one caveat. Not the ownership because that is set to nobody right now.

Tmutil keeps track of it and you can inherit them on another machine/installation. But restoring seems (as far as my research has lead me) also to be limited to tmutil. While I am sure that there are certainly commands that would do this at will they are not documented in

man tmutil

In order to get all data off you will have to run rsync as root. Which will then be the owner afterwards. Alternatively it will set them back to how they were but at nobody as the owner isn't that useful either. The rsync route would allow you to only copy the files that actually exist if you choose to preserve hardlinks. The resulting data set would be about the same size, should be identical in properties with the only difference being that the folders are now not hard-linked. Only the files are.

Personally I would be interested in trying to ask tmutil afterwards to adopt this data set. In any case you will then be able to browse the data freely.

If you just wan't to get all the unique data that is on the time machine disk you can ask fdupes to list hard-links as duplicates (it has a switch for that) and then have them deleted. This should leave you with one unique set. There will still be loads of files that are practically identical but not actually bit for bit. So it might be still messy.

I have gone trough something similar myself. Basically Time Machine should either you once your backup has reached a certain age and tell you to start over. Because it is impossible to restore a working installation from a time machine backup that is a couple of months old (depends on usage, obviously). It simply becomes a really fragmented mess if it has to keep track of millions of files in order to create the consistent set at point X in time. The alternative would be to reconsolidate the sets permanently but that would mean that the resource usage of Time Machine would go up. For mobile computers that would also be unpractical since the disk would need to be connected for extended periods of time. If you like the idea that you can reinstall your computer to the state it was 1h ago before you installed "xy" or did some "rm"ing on something that seemed useless you better keep only 2 or 3 months worth of time machine around (again, depends on usage). Or start using rsync and multiple targets, either with a self written solution or with one of the commercial wrappers around it. Separating the Backup strategy for stored data and working data also helps.

If now someone will turn up an say that using something like ZFS Snapshots would be better then I can only recommend to test that for a couple of weeks and not just blabber on what is written on the internet. This does need considerably more resources to the time machine solution. If it is used for files that change a lot you either end up with pretty gigantic snapshots and are running out of disk space which won't be restored if you delete the snapshots in between. If you even can delete them, which is unlikely. Which only leaves you with the option to delete the oldest ones frequently but in that case Time Machine works absolutely fine as well. From my experience even better. Deduplications would need a very fine graded adjustment since so many files are altered every couple of minutes on OSX but are still kept for years. Incremental backups over a long time seem so of alluring but in practise that might not be the best approach.

Mac – Trouble repairing a corrupt Time Machine sparsebundle on Synology NAS

I got this error message when I tried to restore from my Synology. But I found this

http://thefunkstop.com/fix-corrupted-time-machine-backups/

Turns out that that the "Time Machine user" was never disconnected when my last backup was interrupted. I had to manually disconnect the user and then everything worked when I tried again. But I think it should work by restarting the NAS as well. I hope this can help...

Best Answer

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MacOS – How to save data from a time machine backup that has gone bad

Mac – Trouble repairing a corrupt Time Machine sparsebundle on Synology NAS

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