Suspended HDD is waked up periodically

English Hardware
1

Hello!
I am using ‘hdparm’ to control auto-suspend functionality of one of my HDDs.
(It’s the backup HDD)

Therefor, in init.d/boot.local I’ve added
hdparm -S 235 /dev/sdb
(which are 20min or so)

This works fine, but often the HDD gets awaken for
no reason.

I have on this HDD:

  • no swap partitions
  • no files needed by the system
  • no files opened by applications
  • no temporary files
  • all indexing services are disabled

The only thing is: it’s mounted (but not used in any way).

So, what can it be that wakes up my HDD?

2

Have you figured that out?

3

Temperature checks by monitoring software can wake the disk up.