Trying to get volume efficiency settings but the output is confusing/ambiguous

[HUX20002000]

Model: FAS8300

ONTAP version: 9.15.1

If I do "volume efficiency show -volume [volume] -instance", I see the following fields, which are clear:

• Inline Compression
• Inline Dedupe

However, there are no corresponding fields for "Background Compression" or "Background Dedupe".  There is a field called simply "Compression", but it's unclear what that specifically refers to.

So my question is: How can I confirm at the command line whether or not background compression and background deduplication are enabled?

Related question: For the field "Data Compaction", is that an inline or a background process?

And one more related question: How do the volume-level fields above relate to an efficiency policy applied to the volume? Does the policy only apply to background efficiency settings, even though it can be set to run at a specific time as a "best -effort" (i.e. foreground) process? It's a little confusing!

[TMACMD · Accepted solution]

Anything “background” refers to post process operations. 

on an aff, you generally have in line operations which are immediately effective. 
of fas, unless you have flash pool enabled, then there is no inline without performance penalties.  You either wait for the change log to fill up to trigger a post process operation or you create a policy/schedule to process the secondary/post work when you want it to run

 pretty sure data compaction is done in-line on aff platforms. It is meta data intensive so it may not be worth using on plain spinners (flash pool, maybe ok)

 it only works if you happen to have large numbers of files that are smaller than 4k (wafl block size)