[6.10.2] What is the difference between Use Cache pool types: Yes vs Prefer?

[HDT]

Hello,

 

Under USE CACHE POOLS, it gives us these options:

• Yes
  • indicates that all new files and subdirectories should be written to the Cache disk/pool, provided enough free space exists on the Cache disk/pool.
  • If there is insufficient space on the Cache disk/pool, then new files and directories are created on the array.
  • When the mover is invoked, files and subdirectories are transferred off the Cache disk/pool and onto the array.
• Prefer
  • indicates that all new files and subdirectories should be written to the Cache disk/pool, provided enough free space exists on the Cache disk/pool.
  • If there is insufficient space on the Cache disk/pool, then new files and directories are created on the array.
  • When the mover is invoked, files and subdirectories are transferred off the array and onto the Cache disk/pool.

 

How exactly does PREFER work? 

 

It seems if the Cache disk/pool is full and new files and directories are created on the array, then when would the mover ever transfer files and subdirectories off the array and onto the Cache disk/pool, since it's still full?

 

Which method would one use if one wanted the most recent files and subdirectories to be on the Cache disk/pool until the mover is invoked?  And why?

 

Thank you!

[trurl]

cache-yes is for files you want to be moved to the array where they will be protected by parity.

 

cache-prefer is for files you want to remain on cache for performance. Typically appdata, domains, system shares will be there so dockers/VMs will perform better and not keep array disks spunup since these files are always open.

 

Either will overflow (depending on Minimum Free) to the array when cache is full. When space becomes available, mover will move cache-prefer shares to cache if it can, but nothing can move open files, so often Docker and/or VM Manager will have to be disabled to get those shares moved to cache.

 

If you want more detailed and specific advice based on your current configuration, attach Diagnostics to your NEXT post in this thread.

[dboris]

Hello hello.
I'm having issues with cache getting filled until Docker can't start anymore.

I enabled the secondary storage to fill out the cache.
However, I still want my docker and often read-files to be on the cache.
I also want the cache to offload to array when it's getting full.
However I noticed that the "use cache pool" option is now gone on the GUI.
What should I do to emulate that behaviour ?

This is what I used to have :

 

And this is what I have today ; no more "prefer" option.

 

Thanks !

[SimonF]

13 minutes ago, dboris said:

Hello hello.
I'm having issues with cache getting filled until Docker can't start anymore.

I enabled the secondary storage to fill out the cache.
However, I still want my docker and often read-files to be on the cache.
I also want the cache to offload to array when it's getting full.
However I noticed that the "use cache pool" option is now gone on the GUI.
What should I do to emulate that behaviour ?

This is what I used to have :

 

And this is what I have today ; no more "prefer" option.

 

Thanks !

Change mover action to be Array->ssd

[dboris]

11 hours ago, SimonF said:

Change mover action to be Array->ssd

Thanks again Simon !

It makes sense.  I made several Google search to see if this had been changed and couldn't find anything but this topic.

[SimonF]

27 minutes ago, dboris said:

Thanks again Simon !

It makes sense.  I made several Google search to see if this had been changed and couldn't find anything but this topic.

This should be able to give you more info.

https://docs.unraid.net/unraid-os/manual/shares/user-shares/