# [Solved]hdparm best powersaving settings and one weird story

## DeIM

Hi everyone,

I realized four days back that disks don't want to spin down as before.

Nothing changed, restarting hdparm service didn't help so I decided to reboot machine.

After that It worked fine but today while I was working the disks started to spin without any reason.

After some searching I found that "Advanced power management level" over 127 disables spin down.

So I added -B127 to config and now it seems working.

Before that spin down worked although APM was set to 254.

Now I set my hdparm config to:

```

sdc_args="-B1 -S128"

sdb_args="-B1 -S200"

```

And my question is: What is the best option for APM? What is the minimal value to respect -S option?

Thank you in advance.

PS: I have 750GB and 1TB Samsung disks + SSD for system (my request for quiet PC).Last edited by DeIM on Fri Jan 13, 2012 1:23 pm; edited 1 time in total

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## Bones McCracker

I may get flamed for this, but the best option is to not use hdparm.  I don't think it does any good on reasonably modern hardware.

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## DeIM

Good point   :Wink: 

Now I found while I'm using Kile 2.1, disks starting to spin immediately after this program starts.

Until Kile is closed, disks are happily spinning. No opened files nor files in history on these disks.

Even more weird now  :Shocked: 

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## DeIM

OK now trying with disabled hdparm rc and

/etc/init.d/local.start :

```

hdparm -B128 -S128 /dev/sdc

hdparm -B128 -S200 /dev/sdb

```

After some tests it seems that -B127 sets spin-down to cca 1 min hardly.

Will inform how big success it was after restart  :Wink: 

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## Bones McCracker

There's some good information in here:

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Power_Management_Guide/index.html

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## DeIM

mv /etc/init.d/local.start /etc/local.d/

didn't notice it's local.d in /etc/init.d/local   :Wink: 

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## DeIM

(Wrote post, pressed Preview button, went away for a while and then pressed Submit button, Loged in, post gone  :Sad:  )

OK, seem to be solved for now.

Key is set hdd power saving settings as last boot operation - before login console arise.

*.start file in /etc/local.d/ made this magic.

Wrote shell script which checks certain APM level (-B), if not set then set it.

Then it sets -S. (Not proved but I think order is the key too.)

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