I've recently struggled to understand why my DVR Server running on a Mac started sleeping when I didn't think it should, and this was resulting in interrupted, terminated or missing recordings. This only started happening when I updated Sonoma to 14.3.1 - everything had worked just fine until then. Just in case anyone else stumbles across the same issue, I thought it was worth documenting my experience.
On detail study of the system log, it turned out that even though I had the Energy Saver setting enabled for 'Prevent automatic sleeping when display is off', it was indeed going into sleep for a few seconds, a few minutes, or even significant periods of the order of 100 minutes from time to time.
After a couple of weeks, by listing all the times over a 24 hour period when each sleep period started and stopped - about 30 such periods - I suddenly had the eureka moment when it struck me that they all happened overnight, and not only that, that they were all between the times when I went to bed and got up in the morning. Those are the times when I set my Apple Watch to sleep mode and then unset sleep mode, and surely that couldn't be a coincidence.
Looking at the Focus setting on the Mac, I discovered that there is a setting as to whether you want the focus mode to be shared with other devices, and this was set on by default. (I had never investigated the Focus settings on the Mac as I hadn't considered it of interest.) Disabling that setting, my problems have gone away.
I don't know whether there was bug in this area that was fixed by 14.3.1 so that it is now working correctly, or whether it introduced a bug and Focus mode should not override the Energy Saver setting. However, I am now happy.