MP 7,1 Doubt about hibernatemode, huge RAM and SSD lifespan

[giggles]

Maybe a dumb question, but, would massive RAM like 384GB or 768GB kill the SSD endurance faster if written to disk every time the Mac hibernate?
Is the written file as big as the whole RAM or just used RAM?
Maybe above 64GB people should consider disabling hibernation for good? (and PowerNap too? or it doesn’t matter?)

 

[frankiee]

Maybe a dumb question, but, would massive RAM like 384GB or 768GB kill the SSD endurance faster if written to disk every time the Mac hibernate?

Yes. Another question is how much this matters. Typically even with heavier use of SSDs, it is not easy to wear them out during their lifespan. For example in my current machine, the SSDs are 6 years old (so they are nearing EOL for me), and still 97% "healthy". But still, why wasting ressources if this is not really necessary?

Maybe above 64GB people should consider disabling hibernation for good? (and PowerNap too? or it doesn’t matter?)

I generally do not use hibernation with desktops, and I think it is useless in this case. So yeah, I would say just switch it off

 

[giggles]

I suppose it could matter if the mac hibernated like once or twice every day...I would disable hibernation and use an UPS..

 

[thisisnotmyname]

I don't think desktop Macs truly hibernate (that's a Windows term but whatever the MacOS equivalent level of sleep is) unless you force it via the power management daemon. The sleep that desktops do keeps power to the RAM if I remember correctly. Only laptop Macs write RAM image to disk and only when they are below a level of power that they would risk data loss due to battery going completely dead.

If you mess with the power management from command line to set sleep mode to 3 (or whatever that is where it powers down RAM) then you'd need to think this through.

 

[giggles]

I just wrote “pmset -g” on my desktop mac (2018 Mini) and I read “hibernatemode 3”, that’s “Safe sleep”, so it would write to the SSD every time it sleeps. (good thing I disabled both display sleep and mac sleep on this machine, but that’s another story)

Now, this is an extremely old install that I carried over many times with Time Machine from mac mini to mac mini...maybe I set hibernatemode=3 10 years ago and I forgot..

If someone with a brand new Mac Pro on a new install would do “pmset -g” in terminal we would know what is the default hibernatemode..

 

[frankiee]

At least for me hibernation was also enabled by default.

 

[||\||]

Given how fast newer SSDs are, hibernation and sleep are mostly unnecessary. You are best off shutting down after use.

 

[now i see it]

Don't use Sleep on a workstation

 

[thisisnotmyname]

I've toyed with the idea of using apcupsd and a custom script to force sleepmode 3 when the UPS event hits. In case I was lazy and left something open and unsaved being able to sleep and restore rather than shut down and lose whatever data was present.

Other than that I never sleep a desktop anyway, I just leave them running 24x7 or if I'll be away for an extended period I just shut down.