Time machine backup multiple Macs to the same external storage but each to different volume

[hariv]

I have iMac to back up
And then one external SSD drive to backup.

I have a separate external SSD drive just for Time machine backups.
I created two different volume on this backup drive. one for iMac internal SSD backup , and another for external SSD backup.


So I would like to backup internal iMac. onto a volume on the external timemacine SSD - volumeImac
(This volume should not contain any external drive backup.)

And then backup the connected external ssd drive onto a different volume - volumeSSD of the external time machine drive.
(This volume should not contain any internal drive backup)

Thanks.

 

[DaveSanDiego]

my understanding is the TM makes a single "sparse bundle" located on ONE external location (HDD, NAS etc) for each COMPUTER. So if you have one computer, with X number of drives, the whole system is located in a single bundle... Otherwise TM wouldn't be able to reconcile its contents back to the computer locations.

I have 3 macs all connected to a single NAS... that NAS has 3 sparse bundles , one for each machine. TM made them, and TM manages them

 

[NoBoMac]

Might work, but will need to exclude all internal Mac drive stuff and add the external drive to backup to the options for the second destination TM volume.

Might be able to exclude simply at "/", but guessing that might ignore the external drive, so will need to add "/System", "/Library", "/Applications", "/Users".

 

[hariv]

my understanding is the TM makes a single "sparse bundle" located on ONE external location (HDD, NAS etc) for each COMPUTER. So if you have one computer, with X number of drives, the whole system is located in a single bundle... Otherwise TM wouldn't be able to reconcile its contents back to the computer locations.

I have 3 macs all connected to a single NAS... that NAS has 3 sparse bundles , one for each machine. TM made them, and TM manages them

here my requirement is to backup one Mac. and one external SSD drive.
but I need to know what was backed up from iMac v/s what was on the external drive.

in TM, there is an option to exclude what you don't need, but the issue is, it applies to all the backups.
in simple I just need

computer 1 iMac. backup to. external ssd drive for TM. to volume volumeImac
external ssd drive (some or few partition/volume) backup to. external ssd drive for TM. to volume volumeSSD

currently TM backups everything in iMac and some from external ssd drive to the same backup location/volume.

 

[hariv]

Might work, but will need to exclude all internal Mac drive stuff and add the external drive to backup to the options for the second destination TM volume.

Might be able to exclude simply at "/", but guessing that might ignore the external drive, so will need to add "/System", "/Library", "/Applications", "/Users".

in TM, there is only one exclusion list that can specified and it applies to all the TM back-up.

 

[NoBoMac]

Good catch! Totally forgot about the exclude list.

If don't want to pay for a for-pay solution (eg. Carbon Copy Cloner), can maybe play around with tmutil command line program. Lots of options there for include/exclude lists (ie. try to make "dynamic" exclude lists), what drive to backup to, etc. Might be able to whip up a script that you can then launch via a Launch Agent on a schedule.

 

[hariv]

Good catch! Totally forgot about the exclude list.

If don't want to pay for a for-pay solution (eg. Carbon Copy Cloner), can maybe play around with tmutil command line program. Lots of options there for include/exclude lists (ie. try to make "dynamic" exclude lists), what drive to backup to, etc. Might be able to whip up a script that you can then launch via a Launch Agent on a schedule.

Thanks that makes sense.. I do have carbon copy, but starting from bigSur creating bootable copy, etc have changed... and even carobon copy has a FAQ on it. so I thought i would just prefer and keep it simple with apples own time-machine backup, even though it is not bootable one.. I will also give tmutil a try and see. thx again for your pointer. we can script something and share for the greater good for others.. it might help someone.. thx.