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Default docker appdata location is not a cache-only share If the appdata share is not set to be cache-only, then the mover program will cause your docker applications to become inoperable when it runs (6.1.x). Under 6.2+, this setting should not affect the operation of the application, but it will definitely impact significantly the performance of the application. Fix it via

 

before I go and click on the Appdata Settings Button, and change the settings to Cache only I would like to ask.  why am I getting this message and do I have to do this.

 

Att the moment the only Docker I have installed is Plex,  but in time I am thinking about adding Deluge / VPN , Couch potato and sonarr

 

my Cache is a M.2 250 gb SSD

 

Looking at your diagnostics on another thread recently, I see your appdata is set to cache-yes, and it has been moved to disk1 and is completely on disk1 at the moment. And the same is true of your system share. Setting these to cache-only won't really help at this point since they aren't on cache and mover won't touch cache-only or cache-no shares.

 

The working data for your docker containers is in appdata, and the code for all containers is in the docker image file in the system share. If these shares are on the array, their performance will be impacted by parity updates and they will prevent your parity and array disk(s) from spinning down.

 

The default for these shares was probably cache-prefer. Why did you change them?

 

To get them back on cache where they belong:

1. Go to Settings - Docker Settings and disable the Docker service. Also Settings - VM Manager and disable VMs if they are enabled.
2. Go to Shares - User Shares. Click on appdata and change it to cache-prefer. Do the same for the system share.
3. Go to Main - Array Operations and click Move Now. This will probably take some time since plex in particular has a large number of small files to move
4. After it is finished moving, set those shares to cache-only and re-enable the docker service (and VMs if they are used).

 

 

Hi@trurl

 

Is it possible to leave it on cache-prefer like default?

Or is it a must be to change it to cache-only ?

 

thanks

There is some benefit to having appdata cache-prefer, since it is possible that some applications might have appdata grow to the point of needing to overflow to the array. But just be aware that if it does overflow to the array, there is no way for Mover to move it back to cache with the docker running since Mover can't move open files. I just always make sure that cache has plenty of room.

 

There is no benefit to making system share cache-prefer since that shouldn't grow anyway.

 

I think the reason those shares default to cache-prefer is because some people might install cache after setting them up, but it doesn't really help since nobody knows that they have to stop Docker and VM services to get them moved.

 

More important than all that though, is making sure that cache has Minimum Free set appropriately in Settings - Global Share Settings. In order for anything to overflow, Unraid must decide that cache doesn't have enough room. Unraid has no way to know how large a file will become when it begins to write it. If cache has less than Minimum, Unraid will choose another disk before it begins to write the file. You must set Minimum Free to larger than the largest file you expect to write to cache.

 

Each User Share also has a Minimum Free setting that works in a similar manner. If Unraid sees a particular disk has less than Minimum, it will choose another disk, unless Include/Exclude or Split Level prevent it from doing so.

 

You can always see which disks each of your User Shares is using by going to Shares - User Shares and clicking Compute... for the share, or just use the Compute All button at the bottom of that page.

 

with much thanks 

 

very useful informations !