Q: Time Machine Backups to Server fail
I am having a weird but grave problem.
Setup:
DATASTORE: MacMini (Late 2014), Core i5, 1.4GHz, 16GB RAM, Yosemite 10.10.5 with Server.app 5.0.15, 32TB in a ThunderBay4 cabinet. Everything brand new (1 month old), no reported errors whatsoever (SMART, hardware diagnostics, etc). Had this machine running with el Capitan, too. Same configuration, same issues (s. below)
MY_SERVER: MacMini (Mid 2011), Core i5, 2.3GHz, 8GB RAM, OS X 10.9.5, Server 3.2.2
SOME_CLIENTs: Several MacBooks (pro) with el Capitan Clients, some with, most without Server.app
DATASTORE is set up to provide Time Machine service to the other systems. There are several partitions on those 32TB that are served as TM locations, so different clients can have different quota for their backups as max backup size can only be set per location, not per individual client. :-(
MY_SERVER and the various clients all use DATASTORE as TM destination. All the backups fail more or less regularly with weird error messages like Backup failed with error=(null). Sometimes however backups work for a couple days, then fail again. Sometimes deleting the backup DMG and starting a new backup fixes things.
Interesting fact is that MY_SERVER has been backing up reliably, no hick-ups for several weeks (since the DATASTORE machine was being put into service)
My God, just now, while writing this, I had a failing backup on MY_SERVER. Console.app on MY_SERVER shows these errors:
19. 8. 16 10:44:31.000 com.apple.backupd[93194]: Failed to eject volume /Volumes/tm_miniserver (FSVolumeRefNum: -704; status: -47; dissenting pid: 0)
19. 8. 16 10:44:31.001 com.apple.backupd[93194]: Giving up after 3 retries.
19. 8. 16 10:44:31.006 com.apple.backupd[93194]: Backup failed with error 21: 21
To really clean up things I rebooted MY_SERVER and started a backup manually right after reboot. Now backup fails with yet another nice message: The backup on "datastore" is already in use. And console this time notes
19. 8. 16 11:04:47.663 com.apple.backupd[1104]: Backup failed with error 31: 31
What's that now? Corrupt backup disk image? Somehow locked? Server.app on DATASTORE reports "Backup in progress". How can I fix this?
Each of the clients has a local USB disk that is also used for backup, so the clients are covered. But why is Time Machine to DATASTORE such a fail? Tons of problems.
What I have seen is that CPU load on DATASTORE is rather high, Apple File Service consuming most of the cycles. Could it be that the MacMini is too slow?
Thoroughly confused and at my wits end.
MacBook Pro with Retina display, OS X El Capitan (10.11.6)
Posted on Aug 19, 2016 2:33 AM