Time Machine Backups to Headless Mini File Server

getrealbro

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I’ve recently converted my 2014 Mini into a headless file/music server. Now I’d like to declutter my desk by moving the 8TB Seagate, that is dedicated to Time Machine on my 2018 Mini, to the 2014 Mini.

Since file sharing is already on — Can I just move the 8TB Seagate to the 2014 Mini, select it as the Time Machine disk on my Mini and have Time Machine continue to use the existing Backups.backupdb? Or is there more to it (e.g. does the remote Time Machine backup need to be a sparse bundle)?

Thanks In Advance — GetRealBro
 

djc6

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I tried this and was unable to preserve my old backups.

The "Backups.backupdb" format is when you are backing up to drive connected to local machine. The network backups use a sparsebundle format.
 

getrealbro

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Sep 25, 2015
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I tried this and was unable to preserve my old backups.

The "Backups.backupdb" format is when you are backing up to drive connected to local machine. The network backups use a sparsebundle format.
Thanks. That's what I was afraid of :(

I'll give it a try when I've filled-up/archived the current 8TB Seagate Time Machine drives.

GetRealBro
 

Weaselboy

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select it as the Time Machine disk on my Mini and have Time Machine continue to use the existing Backups.backupdb?
A networked backup like that will put the backup inside a sparse bundle image, but inside that bundle it is still the same Backups.backupdb setup as a local TM disk backup.

Just start your networked backup and give it a couple minutes to make the sparse bundle and begin backing up. Then stop the backup and open the sparse bundle image and delete the Backups.backupdb from inside. Now copy your existing Backups.backupdb from the external disk to inside the sparse bundle image on the networked drive. Then eject the sparse bundle image and you are all set.
 

getrealbro

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Sep 25, 2015
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A networked backup like that will put the backup inside a sparse bundle image, but inside that bundle it is still the same Backups.backupdb setup as a local TM disk backup.

Just start your networked backup and give it a couple minutes to make the sparse bundle and begin backing up. Then stop the backup and open the sparse bundle image and delete the Backups.backupdb from inside. Now copy your existing Backups.backupdb from the external disk to inside the sparse bundle image on the networked drive. Then eject the sparse bundle image and you are all set.
Thanks! It sounds like that process requires a fresh networked backup drive for TM to make the initial sparse bundle. Since both of the 8TB backup drives have roughly a 4TB TM backup that I don’t want to risk, I’ll wait until I buy a new 8TB drive to begin the process.

Thanks Again — GetRealBro
 
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getrealbro

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A networked backup like that will put the backup inside a sparse bundle image, but inside that bundle it is still the same Backups.backupdb setup as a local TM disk backup....
Before committing to multiple remote 4TB+ backups to my headless 2014 Mini file server… I tested the process by backing up only the internal SSD on my 2018 Mini.

I began with a new 8TB Seagate attached to my 2018 Mini via USB, which had been erased/formatted with a GUID partition map and HFS+ Journaled. Note: NOT case sensitive.

1- I used Time Machine to backup just my 2018 Mini’s internal SSD (approx. 160 GB) in roughly 2 hours.

2 - I moved the Seagate to my 2014 Mini and kicked off a remote backup of my 2018 Mini’s internal SSD via Time Machine which created a sparse bundle. This remote backup ran overnight and took over 15 hours.

3 - With both backups on the same disk, I used Time Machine on the 2018 Mini to “Browse other backup disks…” on the 2014 Mini and both backups were fine.

4 - So I deleted the Backups.backupdb in the sparse bundle.*

5 - I tried to replace it by drag&dropping the Backups.backupdb, that had been created while the Seagate was attached to the 2018 Mini, onto the mounted sparse Bundle. But the Finder refused, with the following error message “This volume has the wrong case sensitivity for a backup.”

Get info revealed that the mounted sparse bundle was formatted HFS+ Journaled Case Sensitive :(

So I used Disk Utility to erase and reformat the sparse bundle to HFS+ Journaled (not case sensitve). I’m now copying the Backups.backupdb into the sparse bundle. I’ll post back the results. (see next post)

GetRealBro

* The structure of a Time Machine remote sparse bundle package is very different from the directory structure of a Backups.backupdb. You only get to see the Backups.backupdb that’s inside it, AFTER you mount the sparse bundle, which then appears on the desktop as “Time Machine Backups”.
 
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getrealbro

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The copy of the original Backups.backupdb, that had been created while the Seagate was attached to the 2018 Mini, into the mounted sparse Bundle after I reformatted it to be case insensitive, worked — kind of. But the resulting sparse bundle ended up over twice the size of the original backups — both USB and remote. Of course, being hard headed, I tried it 3 times, with the same result. What’s that definition of being crazy? :(

The copy of the original Backups.backupdb into the sparse bundle would always start by showing the copy progress correctly with xxx GB copied out of 128.86 GB. But then things would get weird. The copy wouldn’t stop at 128.86. It would continue adjusting the amount copied and the target a few MB at a time until the sparse bundle was 368.92GB. The resulting backup in the sparse bundle looks OK. But I don’t trust it. So i’m dropping this project and will keep the 8TB Time Machine backup drives attached to our desktop Macs.

GetRealBro
 
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