Array vs Cache vs Pool (and when to use them)

[EmersonSC]

I've been running unraid for a few months now and first off i have to say its an addiction. I'm constantly searching for new things to add to my setup. I love how easy it is to manage and setup, even the more "complex" stuff.

 

With that said, I have read the documentation, but I'm still confused on how to properly utilize and optimize the different storage options.

 

I have an array setup with thee 8gb HDDs with a 10gb HDD parity. I then have a 1TB m.2 drive as my cache, and two 250gb in the pool.

 

I have all of my personal files on the array, the docker apps and VMs on the Cache, and nothing on the pool as I'm just not sure what its use is.

 

I have an HA and Win11 VM. Docker containers are things like influxdb, next cloud, paperles ngk, etc.

[JorgeB]

16 minutes ago, EmersonSC said:

and nothing on the pool as I'm just not sure what its use is.

There's no right or wrong use, Unraid is very flexible, I have servers without array, just pools, others with only array, no cache or pools, others with both, it really depends on your use case and what you need.

[EmersonSC]

6 minutes ago, JorgeB said:

There's no right or wrong use, Unraid is very flexible, I have servers without array, just pools, others with only array, no cache or pools, others with both, it really depends on your use case and what you need.

I don't know if I necessarily have any specific need. Just want to make sure I'm set up properly and using unraid to its potential. I mostly use it to for my Plex and HA sever as well as the windows 11 VM which has blue iris on it for my cameras. The cameras actually record to a 4gb HDD thats specific use is for NVRs (unmounted and passed through to the VM).

 

I'm also looking to move off my google reliance and use something like Nextcloud. And I love Paperless-ngk because I have a lot of pdf documents from work, medical issues, etc. I found a cool app that helps us organize our huge book of recipes. Plus am working on setting up a couple minecraft servers for my kids. 

[itimpi]

the term cache is often used in two different contexts with Unraid.

 

You can (optionally) have a pool called ‘cache’.   It may or may not be used for ‘cache’ functionality.   For historical reasons the default name for the first pool is ‘cache’.    Personally I think there is a good case for selecting a different default name in the future.
 

The actual cache functionality is set up at the User Share level and is not necessarily linked to the pool called ‘cache’.   It can be used with any pool that is the Primary storage for a User Share

[EmersonSC]

4 hours ago, itimpi said:

the term cache is often used in two different contexts with Unraid.

 

You can (optionally) have a pool called ‘cache’.   It may or may not be used for ‘cache’ functionality.   For historical reasons the default name for the first pool is ‘cache’.    Personally I think there is a good case for selecting a different default name in the future.
 

The actual cache functionality is set up at the User Share level and is not necessarily linked to the pool called ‘cache’.   It can be used with any pool that is the Primary storage for a User Share

 

I'm not going to lie... this left me slightly more confused.

 

Since "cache" and the pool are essentially the same thing, what SHOULD i be doing with them? With all my docker containers in my 1tb cache, should I move some over to the "pool"? Do the cahce/pool drives get utilized in read rights to the array in some way?

[itimpi]

7 hours ago, EmersonSC said:

 

I'm not going to lie... this left me slightly more confused.

 

Since "cache" and the pool are essentially the same thing, what SHOULD i be doing with them? With all my docker containers in my 1tb cache, should I move some over to the "pool"? Do the cahce/pool drives get utilized in read rights to the array in some way?

 

You do not have to have a pool called 'cache' - this is optional as you can give a pool any name you like.     That does not stop a pool being used as the 'cache' for a User Share as you set that up at the User Share level and can select any pool you have to provide the cache functionality for that particular share.   Different User Shares can potentially use different pools to act as their 'cache' although that is rarely the way Users do it.