Is the docker.img file constantly in use?

[cybersteel8]

I am curious about the benefit of setting the system share on Cache Prefer.

I use the tool that backs up my appdata onto the array (as it is also cache prefer) but I don't have such functionality for the system share, so it currently only exists on the single cache disk I have.

 

I would like to know if there is any benefit in keeping this share on the cache at all times - in other words, is the docker.img file that is inside it constantly in use while docker containers are running? I only restart my docker containers when there is an update to be applied, and I assume that is when the docker.img file is used. But otherwise, is the file in use at all?

 

If it isn't, then there's no point keeping it on the cache, right?

[Squid]

The docker.img is in constant use depending upon what the apps etc are doing.  (And even if all apps are stopped, then it is still open for use)

 

Not placing it on your cache drive will result in a performance penalty from the containers.  (Along with keeping multiple drives spinning on your array)