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Saving Power


I wanted to save power due to the high energy prices. I have a NAS running 24/7.

It turns out the there is a way to program the RTC in the NAS to wake up on a specified time: rtcwake.

First I needed to ensure that if my RTC was in UTC;

➜  ~ timedatectl
               Local time: Tue 2022-10-04 20:55:19 CEST
           Universal time: Tue 2022-10-04 18:55:19 UTC
                 RTC time: Tue 2022-10-04 18:55:19
                Time zone: Europe/Copenhagen (CEST, +0200)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Then I can create a cron job that issues the rtcwake at the right time:

0 22 * * * /usr/sbin/rtcwake -m off -s 43200

So every day at 22 hours (10pm) turn the NAS off, and set the wakeup to be 43200 later (12 hours)