Under "Get Info" --> "Available" what does purgeable mean?

[Luba]

Under "Get Info" --> Available: 22.5 GB (9.2 GB purgeable)

What does purgeable mean? I'm trying to figure out how much meaningful storage I have left.

I think I'm supposed to have free at least 10% of capacity?? Under "Get Info" --> Capacity: 121.12 GB so 22.5 - 12 (10%) = 10.5 GB. I can store 10 GB more? But what does 9.2 GB purgeable mean?

 

[T'hain Esh Kelch]

Purgeable storage consists of files that macOS deems suitable for removal. Something that can be literally purged away from your drive and cause no trouble. The appearance of Purgeable storage is connected to the feature of Optimized storage in macOS. When Optimized storage is turned on, loads of files get moved into the cloud and for some of them, actual presence on your drive is optional. But for which exactly?

 

[Luba]

So for Available: 22.5 GB (9.2 GB purgeable) I actually could have 22.5 GB + 9.2GB of storage to use??

 

[T'hain Esh Kelch]

In principle yes, but your system will then start removing files (Which you can of course just download from the cloud again, but you'll need space to do so). Also, you'll want at least 20GB space free on your boot disk, otherwise the OS will start to slow down due to lack of system caching.

 

[Luba]

In principle yes, but your system will then start removing files (Which you can of course just download from the cloud again, but you'll need space to do so). Also, you'll want at least 20GB space free on your boot disk, otherwise the OS will start to slow down due to lack of system caching.

To prevent system slow downs how do you determine the amount of boot disk free space needed? Is it a certain percentage of the boot disk or is it just a flat amount of 20 GB? My total boot disk size is 120 GB.

 

[T'hain Esh Kelch]

It is based on personal experience. Back in the days it was about 10% of the drive. But now a flat 15-20GB is where I don't see any effect on the OS.