Compact Flash/USB Install for Low-Power Application

Question

I posted this question in the "Free Tools" section but I wasn't sure if it would be more appropriate to post it here because I think the tool ( Sophos UTM Essential Firewall ) is the free version of the UTM 9 product. If this is incorrect please let me know and/or delete this question and I apologize in advance. 
 I'm working on a UTM build and have narrowed down the choices to either Sophos UTM Essential Firewall or pfSense. I'm trying to drive the power consumption as low as possible since the device will remain powered on 24/7. One of the ideas I had was to use either compact flash (CF) or USB jump drive as the bootable source for the OS in lieu of a traditional spinning platter/SSD hard drive. The obvious problem here is that flash media and writes generated by logs/OS don't play nicely with one another and will cause premature failure of the flash media. 
 Here is what I know: 
 There is a post on the forums from 2005 talking about installation to CF media. I wasn't able to find anything newer but it could be the search terms/methods I was using. 
 I fully appreciate that SSD/Laptop typical and peak power draws are already very low. I am looking to squeeze every last watt out of the system's average consumption. 
 pfSense has a feature to force /var and /tmp to reside exclusively in RAM. Long term retention of logs is achieved from syslog server. Values in those areas are written on graceful shutdown and obviously lost on unexpected power event. 
 My questions to the community: 
 Is it possible to install UTM 9 onto flash media (in my case, 64GB USB 3.0)? 
 Does UTM 9 have similar RAM disk and syslog capabilities to minimize wear on the flash media?

dirkkotte · Accepted Answer

there are no official RAM cache capabilities at UTM. 
 you should consider to take a micro ssd yet. 
 micro SSD's (here Samsung EVO 850 ) take 0,02W idle to 1,8W R/W ... and they are designed for many writes too. 
 the additional memory to cache current logfiles need more power ... i think.

BAlfson · Answer

Hi, Christopher, and welcome to the UTM Community! 
 This is the correct forum for your UTM question. The other forum is a catch-all for the other Sophos free tools. 
 Agreed with Dirk. Don't use a USB stick as your hard drive. You will burn it out in a few months. Buy a good SSD that connects to a drive interface or has its own. 
 The Essentials license is for a business. If this is a home-use situation where you aren't running a businesss from your home, you can get a free home-use license that gives you access to the entire UTM capabilities with very few limitations. 
 Cheers - Bob