Time Machine via SMB with Mac OS Big Sur

  • Hi,

    I cannot create time machine after upgrade to Mac OS Big Sur.

    It was happily running with Catalina.

    I removed old sparse bundle and then when trying to create new backup it creates spase bundle and then removes it again.

    DIsk is formatted in EXT4.

    What am I missing?

    Latest updates to OMV 5 installed.

  • Been playing around with this also after upgrading to Big Sur, but cannot get it to work! TimeMachins fails with "error 112: no mountable file systems".

    Googled a bit, and added this to my TimeMachine share (SMB/CIFS) on ext3/ext4:

    vfs objects = acl_xattr catia fruit streams_xattr
    fruit:nfs_aces = no
    inherit permissions = yes
    min protocol = smb2

    It now starts backing up, and gets about half to 2/3rds into the backup, and then gives up! It then sits at "Waiting to complete first backup"! If I restart it, it starts "Preparing backup" and gives up after a couple of seconds! This pattern is repeatable!

    It seems like others have gotten it working, so it should be possible! Here is a dude that have it working on a Raspberry Pi: https://saschaeggi.medium.com/…with-big-sur-1e66a9650789

    And also these guys on other machines:


    Anyone out there with luck on this on OMV, or any hints on what to try? Would hate to have to build a separate setup just for TimeMachine!

  • Hmm, found this on reddit (https://www.reddit.com/r/MacOS…achine_on_samba_broken/):


    got it to work, though I am not sure my solution will work for those not using zfs

    I had my vsf objects in the correct order

    I replaced vfs objects = catia fruit streams_xattr zfsacl

    with vfs objects = zfsacl catia fruit streams_xattr

    So, it would seem my change above (vfs objects = acl_xattr catia fruit streams_xattr) is similar, but for NTFS (https://www.samba.org/samba/do…html/vfs_acl_xattr.8.html). So now we have the ACL-parameter for ZFS and NTFS. My problem is, I run ext3/etx4 on my NAS, and I do not see to be able to find the corresponding ACL-setting for ext-filesystems!

    Any ideas?

  • FYI I was able to get Time Machine working to a test Big Sur VM and got Global Quotas working. All credit goes to jbowen.dev at the link below.


    Create a file .com.apple.TimeMachine.quota.plist as the root user with the following contents, please note the period before the com is important as it makes the file hidden. Once you have created the file make sure to set the permissions with chmod 644 .com.apple.TimeMachine.quota.plist The file below is an example with a quota of 500GB. I tested this and once the time machine created the sparse bundle you can look at the Info.plist inside the bundle to make sure the quota took. This is not a limit for the whole folder rather it's a limit per client. This was done on a OMV 5 machine with a 3tb disk formated BTRFS.

    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
    <plist version="1.0">
  • What settings do you have/add to you SMB/CIFS and your Time Machine share?

    Are you saying these quotas are needed, or optional to get it working?

    I can get it to do an initial backup, but after that it throws errors for all manual or hourly backups after that.

    Errors like this:


    2021-03-21 23:23:07.533941-0500 0x6453 Info 0x0 1585 0 backupd: (TimeMachine) [com.apple.TimeMachine:General] Backup cancel was requested.

    2021-03-21 23:23:17.630145-0500 0x6453 Error 0x0 1585 0 backupd: (TimeMachine) [com.apple.TimeMachine:General] backupd exiting - cancelation timed out



    2021-03-21 23:12:12.275244-0500 0x433f Error 0xc351 252 0 backupd: (TimeMachine) [com.apple.TimeMachine:General] Failed to unmount '/Volumes/.timemachine/NAS-OMV - SMB\/CIFS._smb._tcp.local./22879FD3-1AC5-4D7F-BFB2-F8107ABEF0B2/TimeShare', error: Error Domain=com.apple.diskmanagement Code=0 "No error" UserInfo={NSDebugDescription=No error, NSLocalizedDescription=No Error.}



    2021-03-21 23:12:05.885016-0500 0x4d38 Error 0x0 252 0 backupd: (TimeMachine) [com.apple.TimeMachine:General] Failed to mount APFS snapshot with name 'com.apple.TimeMachine.2021-03-21-191717.backup' on volume '/Volumes/Backups of EMB-82JGLVDR' at mountpoint: '/Volumes/.timemachine/C2F98D57-DAFE-4A6A-B7F0-97E7F3D62E98/2021-03-21-191717.backup', error: Error Domain=NSPOSIXErrorDomain Code=5 "Input/output error"

    2021-03-21 23:12:05.885156-0500 0x4d38 Error 0x0 252 0 backupd: (TimeMachine) [com.apple.TimeMachine:General] Failed to mount backup snapshot 'com.apple.TimeMachine.2021-03-21-191717.backup' at '/Volumes/.timemachine/C2F98D57-DAFE-4A6A-B7F0-97E7F3D62E98/2021-03-21-191717.backup, error: Error Domain=NSPOSIXErrorDomain Code=5 "Input/output error"

    2021-03-21 23:12:05.885264-0500 0x4d38 Error 0x0 252 0 backupd: (TimeMachine) [com.apple.TimeMachine:General] Failed to mount backup 2021-03-21-191717.backup error: Error Domain=NSPOSIXErrorDomain Code=5 "Input/output error"

    This is getting really frustrating! Have had to resort to an external USB to at least have a backup! Should not be needed, and will not work once I upgrade the rest of the family machines to Big Sur!

  • Here is another attempt:

  • And this:

  • And this:

    and then it fails again.

  • Sorry I didn't have any issues with my virtual doing backups to the test SMB folder I setup. I didn't do anything special just enabled time machine on the share and setup the timemachine on the MacOS VM. Try and delete the folder in OMV and re-create the backup as it may have gotten corrupt.

  • Well, for me I had to add:

    vfs objects = acl_xattr catia fruit streams_xattr

    fruit:nfs_aces = no

    Before it would not even do a backup! But now, even if I can get it to do a full backup, it will not do the incremental ones!

  • I wonder whats going on here.

    I upgraded from Catalina to Big Sur several weeks ago. And i have no issues with TM to an SMB-Share of OMV 5. No "special settings/options" needed.

    Did you set the option "Time Machine Support" in SMB-Settings?

  • I have Time Machine working just fine on my Catalina-machines (3, one for each of my family-members) but not my Big Sur machine.

    You are talking about the "button" for the share, right? It has been on all the time!

  • I know this doesn't answer your question and doesn't solve your SMB problem, but because of those troubles and slow transfer speeds and slow folder refreshing and ...., I decided to use AFP again. AFP works out of the box for me on my M1 MacBook instead of SMB, SMB and MacOS isn't the way to go for me.

    Netatalk: forum.openmediavault.org/index.php?thread/28632-netatalk/&postID=238657#post238657

    Hewlett-Packard HP t630 (AMD Embedded G-Series GX-420GI | QuadCore | 8GB)
    6.0.41-1 (Shaitan) | 64 bit | Linux 5.15.53-1-pve | omvextrasorg 6.1.1

  • saber-rider1

    Ofcourse I know that, but as stated, my Catalina machines still backup just fine to the same destination, this should prove that it is most likely not any of those issues!

    I also know of this trick:

    Speeding up:


    To speed up, type:

    # sudo sysctl debug.lowpri_throttle_enabled=0

    How to revert to your normal CPU activity:

    # sudo sysctl debug.lowpri_throttle_enabled=1

    Using this trick, I have managed to finish the initial backup on Big Sur several times, but incremental never works after this!

  • Hmm, think I know what it is now! Found other people having issues with TimeMachine-backups on Big Sur if Sophos was installed, I do not have that, but on my work-machine I have "Crowdstrike Falcon".

    Updated one of my private machines to Big Sur, and Time Machine works just fine on it!

    So, it must be an issue with "Crowdstrike Falcon" on the work-machine! Will open a ticket with them!

    Sorry for the "red herring"!

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