[kwlug-disc] Encrypted disk vs Encrypted Home

[Chris Irwin]

On Thu, Apr 23, 2020, at 19:15, Ron Singh wrote:
> I use laptops exclusively, I use Linux Mint all day long for my various jobs. I have a fleet of older Thinkpads I use for each biz/client.
> 
> I grow more fearful of having my laptop du jour stolen.
> 
> I have 3 identical laptops set up with Mint 18.2(based on Ubu 16.04 LTS) with the same power profile(using TLP).
> One has no encryption, 1 has encryption only on Home, the last has the entire SSD encrypted.
> - No encryption, idle temp is 39-40C (no issues on lap)
> - Encrypted Home, idle temp is 42-45C (warm on lap but not uncomfortable)
> - Encrypted Disk, idle temp is 46-50C (uncomfortable as hell on lap)

Does your workflow do a lot of Disk I/O? I can't imagine "normal" desktop use performs enough disk I/O to cause a 5-10 degree rise in temperature...

As all the laptops are otherwise identical, have you tried swapping hard drives to confirm the only differing factor is disk encryption, and not something like the heatpipe being loose, failing fan, etc. (I've seen improved temperatures by reinstalling the heatpipes on my older thinkpads).

FWIW, I'm on a Sky Lake t460 with full-disk luks, and my current CPU temp is also ~46°C, but I also have a consistent load average of >2 right now. Additionally, the dock blocks half the fan exhaust.

However, the laptop still doesn't appear warm to the touch (granted, it's not on my lap), and I've never noticed it being particularly warm when on my lap unless I start putting unusual load on it, or block the fan intake with my clothes.

I'll run wireless for a bit tomorrow and check temperatures to compare.

> Any ideas on how to get that Encryted Disk temps down? I have the CPU locked down at 1.2Ghz max(from 2.6Ghz), unused ports go to sleep, running an SSD, fan is set for aggressive blowing to reduce internal chassis temp.

I've reverted back to just standard Fedora config at this point. I see thermald is running, but I don't have TLP installed anymore.

I do appear to be on the powersave governor, though I'm not sure why/how that was set. I'm somewhat surprised it wasn't ondemand...

I believe there is a UEFI setting for system performance (on battery, on ac, etc), but couldn't tell you what mine is set to.

-- 
*Chris Irwin*

email: chris at chrisirwin.ca
 xmpp: chris at chrisirwin.ca
 web: https://chrisirwin.ca
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://kwlug.org/pipermail/kwlug-disc_kwlug.org/attachments/20200424/d32142ac/attachment.htm>