Share size limit for Time Machine backups?

[CiaoCiao]

Hello everyone,

I've seen a few (very) old topics including statements that a share size limit was under development.

Yet, I have not found this feature in my new (and first) unRAID system.

 

Time Machine is great because it is very simple to setup. But the problem is that it only overwrites old backups with new ones when there is not enough space left to write a new one without overwriting old ones.

 

So this means it could potentially fill-up all the disks of the share.

 

Of course you can setup a minimum free space but this is not really what I'm looking for since the disk is also used by other shares.

 

How can I limit the size without having to plan on how I use the free space of the disk?

 

Thank you  

[Squid]

3 minutes ago, CiaoCiao said:

I've seen a few (very) old topics including statements that a share size limit was under development.

May have been suggested at one point or another, but definitely never implemented, short of confining a share to a drive or 2 

[CiaoCiao]

5 minutes ago, Squid said:

May have been suggested at one point or another, but definitely never implemented, short of confining a share to a drive or 2 

 

Alright! Thank you for your reply.  

 

Hum... So there is basically no other solution right?

[John_M]

18 minutes ago, CiaoCiao said:

Hum... So there is basically no other solution right?

 

Wrong! There is, but it's a little complicated. Do you understand how Time Machine works when the destination is on a network share instead of on a locally attached hard disk? For each Mac that's being backed up Time Machine creates a sparse bundle disk image. The disk image provides the HFS+J volume needed to store a set of Time Machine backups and so a double mount is needed: firstly, the Mac must mount the network share served by the file server; and secondly, it must mount the sparse bundle disk image. Normally this disk image is allowed to grow until it fills the share. It is possible, however, to set a maximum size on the disk image. There's information here. (It's an archive of James Pond's (a.k.a. Pondini's) website. Sadly, the author died in 2013 so it is no longer maintained but there's a wealth of information about Time Machine that is still relevant today.)