New external HD (LaCie d2 Professional 10TB), first configuration. I have planned to use it for backups of two different Macs, for each TimeMachine and each CarbonCopy Cloner. What makes more sense in the initial configuration: create several APFS-Volumes to ONE container - or separate the container in separate Partitions?
Mac Studio (2022)
For your 10 TB LaCie d2 Professional, I would use one GUID Partition Map, one APFS container, and four separate APFS volumes: one Time Machine volume and one CCC volume for each Mac.
APFS volumes within the same container share the container's available space, while optional quotas can limit how much space an individual volume may use. (Apple Support)
This arrangement is also consistent with CCC's current guidance. CCC recommends a dedicated volume for each Mac when backing up multiple Macs to the same APFS-formatted disk.
When Time Machine and CCC share the physical disk, CCC recommends giving Time Machine its own dedicated volume and applying a quota to it so that Time Machine cannot consume the space needed by the CCC volumes. (Bombich Support)
Your initial layout would therefore be:
LaCie d2 Professional 10 TB
└── GUID Partition Map
└── APFS Container
├── Mac 1 — Time Machine
├── Mac 1 — CCC
├── Mac 2 — Time Machine
└── Mac 2 — CCC
I would not create four separate physical partitions.
The APFS volumes provide the separation needed between the backups while allowing the 10 TB container's free space to be shared.
The two Time Machine volumes should have quotas appropriate to the amount of data on each Mac and the amount of Time Machine history you want to retain.
Apple confirms that Time Machine can use an APFS volume and that APFS volumes in a container share available space. (Apple Support)
One further consideration is that this 10 TB disk is a single physical device.
Separate volumes protect against accidental mixing of backup data, but they do not protect against failure of the LaCie drive itself.
A second backup device would therefore provide substantially better protection against physical-disk failure.
Apple's relevant documentation is here: Add, delete, or erase APFS volumes in Disk Utility and Back up your Mac with Time Machine.
To truly protect your non replaceable Data
Have a 3-2-1 Rescue Plan in place and always current
3 Backups using 2 methods and 1 off site incase of natural disaster or un-natural disaster.
Each of the above should be done to a Dedicated Single Purposed External Drive
Below link is intended to augment what TM Backup does
For your 10 TB LaCie d2 Professional, I would use one GUID Partition Map, one APFS container, and four separate APFS volumes: one Time Machine volume and one CCC volume for each Mac.
APFS volumes within the same container share the container's available space, while optional quotas can limit how much space an individual volume may use. (Apple Support)
This arrangement is also consistent with CCC's current guidance. CCC recommends a dedicated volume for each Mac when backing up multiple Macs to the same APFS-formatted disk.
When Time Machine and CCC share the physical disk, CCC recommends giving Time Machine its own dedicated volume and applying a quota to it so that Time Machine cannot consume the space needed by the CCC volumes. (Bombich Support)
Your initial layout would therefore be:
LaCie d2 Professional 10 TB
└── GUID Partition Map
└── APFS Container
├── Mac 1 — Time Machine
├── Mac 1 — CCC
├── Mac 2 — Time Machine
└── Mac 2 — CCC
I would not create four separate physical partitions.
The APFS volumes provide the separation needed between the backups while allowing the 10 TB container's free space to be shared.
The two Time Machine volumes should have quotas appropriate to the amount of data on each Mac and the amount of Time Machine history you want to retain.
Apple confirms that Time Machine can use an APFS volume and that APFS volumes in a container share available space. (Apple Support)
One further consideration is that this 10 TB disk is a single physical device.
Separate volumes protect against accidental mixing of backup data, but they do not protect against failure of the LaCie drive itself.
A second backup device would therefore provide substantially better protection against physical-disk failure.
Apple's relevant documentation is here: Add, delete, or erase APFS volumes in Disk Utility and Back up your Mac with Time Machine.
To truly protect your non replaceable Data
Have a 3-2-1 Rescue Plan in place and always current
3 Backups using 2 methods and 1 off site incase of natural disaster or un-natural disaster.
Each of the above should be done to a Dedicated Single Purposed External Drive
Below link is intended to augment what TM Backup does
An important point is to limit the size of the TM backups so that one of the Macs does not take more than it's 'fair share' of the backups. Volumes in a APFS container are dynamic, meaning if one Mac has files changed more frequently, that Mac will outcompete the other one for space.
You can mitigate that possibility in two ways. One, by using partitions instead of volumes when formatting the drive initially (you can't practically change them later). The other way is by limiting the size of the TM backup for each Mac when you first set up that TM backup, there is an option to set a Disk Usage Limit.
Personally, I back up 5 Macs to a partitioned SSD, with each partition sized appropriately for the Mac being backed up.
Hard partitions make sure no single backup will use the entire 10TB.
A single APFS file system, with multiple volumes, all share the same free space, so any 1 volume could use up all the space.
I never recommend using multiple partitions on a drive because people almost always realize much later that one or more of them are too small. The only way to fix that mistake is by erasing the whole drive and starting over.
However, @BobHarris' concern is valid as is @Ikrupp's concern of putting your eggs in one basket. The suggestion by @neuroanatomist to limit the size of a TM backup when creating the first TM backup for each backup may be the better option when using a single drive, but that will still likely result in being a permanent setting like that of hard partition sizes so you still a similar issue, but at least it would only be limited to each backup created with a limit in place so the damage may be less severe.
If you have a lot of data, then having multiple backup drives and locations is best as is having more than one backup method.
First of all, backing everything up to a single storage device is begging for an eventual catastrophe. If the device fails you lose all your backups. Your Time Machine and Carbon Copy Cloner backups should at least be on different storage devices. If you value your data (Photos, Emails, Videos, etc) you must have as failsafe a backup strategy as possible and having all your eggs on one basket isn’t it.
I strongly recommend your reconsider your plan.
lkrupp wrote:
First of all, backing everything up to a single storage device is begging for an eventual catastrophe. If the device fails you lose all your backups. Your Time Machine and Carbon Copy Cloner backups should at least be on different storage devices. If you value your data (Photos, Emails, Videos, etc) you must have as failsafe a backup strategy as possible and having all your eggs on one basket isn’t it.
I strongly recommend your reconsider your plan.
Ah, the Humpty Dumpy effect lol
APFS volumes vs. separate partitions for external Mac backups
