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AAM, Acoustic Level, what's minimum what is maximum?

ovizii

Senior Member
Joined
Jun 30, 2014
Messages
432
Provided my disks understand AAM, which setting would make them the quietest, minimum or maximum?
I'm not sure if those values refer to the noise or to the amount of throttling?
 

mav@

iXsystems
iXsystems
Joined
Sep 29, 2011
Messages
1,078
According to ATA-7 specification:
Reserved FFh
Maximum performance FEh
Intermediate acoustic management levels 81h-FDh
Minimum acoustic emanation level 80h
Retired 01h-7Fh
Vendor Specific 00h
 

ovizii

Senior Member
Joined
Jun 30, 2014
Messages
432
great, thanks, and what corresponds to the minimum/maximum drop-down selection in freeNAS?
 

seb101

Member
Joined
Jun 29, 2019
Messages
73
Sorry to zombie this thread but I notice the OP's question never got answered.

I too am interested in what AAM levels 'Minimum' 'Medium' and 'Maximum' in the Freenas dropdown equates to.

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!
 

G8One2

Member
Joined
Jan 2, 2017
Messages
155

G8One2

Member
Joined
Jan 2, 2017
Messages
155
I think it's specific to devices that are compatible. I'm not sure about this, but i suspect you need a certain ATA device for this feature.
 
Joined
May 11, 2012
Messages
42
Sorry to zombie this thread but I notice the OP's question never got answered.

I too am interested in what AAM levels 'Minimum' 'Medium' and 'Maximum' in the Freenas dropdown equates to.

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!
Great questions, I am not a developer or support on the FreeNAS project but I am someone who knows my way around source code so I did some cursory searching of the codebase. Found the following:

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


That's on the maser branch right now, no idea how branching works for this project but we can probably assume the numbers are ascending from minimum up.

Based on:

The ATA/ATAPI sub-command for setting the level of AAM operation is an 8-bit value from 0 to 255. Most modern drives ship with the vendor-defined value of 0x00 in the acoustic management setting. This often translates to the max-performance value of 254 stated in the standard. Values between 128 and 254 (0x80 - 0xFE) enable the feature and select most-quiet to most-performance settings along that range.
It sounds like Maximum is the quietest. But wikipedia is also saying the feature isn't even enabled until 128, so I am not sure what might be going. For my system I personally don't hear a difference between MINIMUM or MAXIMUM.
 
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