writing to cache keeps array spinning


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Hello,

 

I have a docker container that regularly writes to a share that is set to `Cache: yes`. I assume it is then writing to the cache. I also assume nothing else is writing to the array that regularly (I'm like 99% sure). The mover runs much less frequently than the docker container writes. Thus, I expect the array to spin down. I does not spin down.

 

The docker container writes every 10 minutes

The mover moves once a day (outside the time I am testing this issue)

The spin-down delay is 30 minutes

 

I switched the share to `Cache: prefer`. Then eventually the array spun down. I must not be understanding how the spin-down delay and the cache interact. Does anyone have some kind of explanation for this? And also, is there a way I can set the share to `Cache: yes` and have the array spin down as I expect?

 

Thanks in advance for any info!

 

 

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  • Solution

If the container is referencing or writing to any files that have already been moved to the array, the array will stay spun up. Cache: yes means NEW files written to the share will be on the cache, then when mover runs they will be transferred to the array if they aren't being held open by something.

 

Cache: prefer will attempt to move the entire contents of the share to the cache drive, assuming there is enough free space. Once again, any files that are open will fail to move.

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10 hours ago, JonathanM said:

If the container is referencing or writing to any files that have already been moved to the array, the array will stay spun up. Cache: yes means NEW files written to the share will be on the cache, then when mover runs they will be transferred to the array if they aren't being held open by something.

 

Cache: prefer will attempt to move the entire contents of the share to the cache drive, assuming there is enough free space. Once again, any files that are open will fail to move.

 

Thanks for the explanation!

 

I was hoping the share on `cache: yes` would always write to the cache first, then the mover would update. That way old files in the share just chill in the array where regularly used ones are on the cache. But I see now that `cache: prefer` is the way to go if there are ever going to be any files that frequently get written to.

 

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