Acoustic Management Levels

[seb101]

Hi,

Can someone enlighten me as to what the GUI dropdown AAM levels 'Minimum' 'Medium' and 'Maximum' in the Freenas equates to in hardware?

Firstly, it's ambiguous as to whether Minumum is:
1. Minimum Acoustic Output (i.e. quitest)
2. Minimum Acoustic Dampening (i.e. loudest)

Secondly, it would be good to know what ATA specification levels (128 to 254 (0x80 - 0xFE)) each one corresponds to.

Thanks!

 

[seb101]

Well... things get a little weird here...

In the source code, the levels are assigned as follows (https://github.com/freenas/freenas/blob/master/src/middlewared/middlewared/plugins/disk.py) line 1805

Code:

            acousticlevel_map = {
                'MINIMUM': '1',
                'MEDIUM': '64',
                'MAXIMUM': '127',
            }

However this is then set via the camcontrol aam command (line 1813). However the man page for camcontrol states:

Code:

optional parameter (-l) specified, enables and sets automatic acoustic management level, where 1 -- minimum noise, 254 -- maximum    performance

This means that the 'max' in the GUI is not actually the max performance of the drive. Is it supposed to be?

However! This is further confused because the AAM ATA specification states:

Code:

 Values between 128 and 254 (0x80 - 0xFE) enable the feature and select most-quiet to most-performance settings along that range

So I'm thouroughly confused. Does the camcontrol command do the conversion between the input value (1 to 254) and the correct AAM enable values (128-254)? Can a dev please shine some light?