Hard Drives spin down faster than expected (1-2 minutes)

[dheinz]

Hi TrueNAS experts,

I am running TrueNAS-13.0-U5.3 on a small NAS with 4x 4TB drives. The NAS is only used for ~weekly backup operations and occasional archive retrieval, so I've had it set to spin down the drives the rest of the time. The thing I'm finding, however, is that the drives spin down far faster than specified.

The drives are configured with the options copied at the bottom of this post. As I understand it, they should spin down 300 minutes after the last activity. However, it seems that they spin down after less than 2 minutes. This results in frequent spin up/down cycles, and annoyingly laggy behavior after just a moment of inactivity. Does anyone here have any idea why this is, or what I can do about it, short of disabling the power saving all together?

Thank you so much!

Model:ST4000VN008-2DR166​

Transfer Mode:Auto​

Rotation Rate (RPM):5980​

HDD Standby:300​

Adv. Power Management:127​

Acoustic Level:DISABLED​

Enable S.M.A.R.T.:true​

S.M.A.R.T. extra options:​

 

[Volts]

The GUI help-text says "minutes of inactivity". But SMART standby timers are completely insane, so I wonder how that's implemented within TrueNAS.

From smartctl(8):

A value of 0 or 'off'
disables the standby timer. Values from 1 to 240 specify
timeouts from 5 seconds to 20 minutes in 5 second increments.
Values from 241 to 251 specify timeouts from 30 minutes to 330
minutes in 30 minute increments. Value 252 specifies 21
minutes. Value 253 specifies a vendor specific time between 8
and 12 hours. Value 255 specifies 21 minutes and 15 seconds.
Some drives may use a vendor specific interpretation for the
values. Note that there is no get option because ATA standards
do not specify a method to read the standby timer.

If you set it to 240, do you get something more like 20 minutes?

 

[Davvo]

Considering the following script might be worth.

HDD Spindown Timer

Disk spindown has always been an issue for various TrueNAS / FreeNAS users. This script utilizes iostat to detect I/O operations (reads, writes) on each disk. If a disk was neither read nor written for a given period of time, it is considered...

www.truenas.com