APFS sparse bundles on MyCloudEX2Ultra

[Michael99]

Hi,

I’m a new My Cloud EX2 Ultra user (with Firmware 5.21.104) and I’m asking myself what’s the “magic” behind the system provided “TimeMachineBackup” share…

I successfully configured Time Machine on my iMac (Intel, Big Sur 11.6.5) to use the “TimeMachineBackup” share. Time Machine created an APFS sparse bundle for its backups in that share and all seems to be okay. I didn’t touch the My Cloud Time Machine default setting of 100% storage due to the unsolved problem with size reductions discussed in other topics in this forum.

Then I tried to integrate Carbon Copy Cloner (CCC) in my backup strategy. I want it to create a daily clone of my system to an APFS sparse bundle on my My Cloud. I created a new share for that and tried to create the APFS sparse bundle with disk utility directly in that new share. This fails with RPC error 73 in disk utility!

I then tried to create a HFS+ sparse bundle directly in the new share… and this worked! So for now CCC is creating and updating the clone in this HFS+ sparse bundle.

But… how could Time Machine create and use an APFS sparse bundle and I am “restricted” to HFS+ sparse bundles? I know I cloud create the APFS sparse bundle outside of my My Cloud and then move it to the share… but the web is full with complaints that this will result in failures to locate or mount the sparse bundle after a short time.

At last I tried with disk utility exactly what Time Machine did: Creating an APFS sparse bundle in the “TimeMachineBackup” share. And this works!

I double checked it with the “Public” share and all other self created shares: None of them accepts the creation of APFS sparse bundles from disk utility, only “TimeMachineBackup” does. HFS+ sparse bundles can be created everywhere.

So: What’s the “magic” with the system provided “TimeMachineBackup” share?
It’s settings in dashboard don’t like different from other shares… and I would like to configure shares “of this kind” of my own being able to host APFS sparse bundles.

This is because in my setup CCC is using an external WD MyBook drive USB-connected to my My Cloud, which automatically creates a share I can use to access this drive from CCC. And this share can’t host APFS sparse bundles - and as I already said: no other share can do that, except the provided “TimeMachine Backup” share.

Again: What’s the “magic” with the “TimeMachineBackup” share and how can I “clone” it’s settings to other shares - making them ready for APFS sparse bundles?

Best regards,
Michael

[Keerti_01]

Hi @Michael99,

Have you opened a Support Case? If not opened, for more information, please contact the WD Technical Support team for the best assistance and troubleshooting:
https://support-en.wd.com/app/ask

[Michael99]

Hi @Keerti_01,

no, I didn’t open a support case yet, because I’m just curious what you (WD) do “behind the scenes” with this special Time Machine share. This is not a (severe) problem with the product, it works as advertised. But thanks for encouraging me - I will do that now.

[Michael99]

I opened a support case several days ago and just received the final answer:

This is expected behavior. That’s it. No explanation about the “magic” with the special “TimeMachineBackup” share or how to “clone” this special handling of APFS sparse bundles.

Seems that I have to live with it as it is without understanding it.