Just trying to find out a bit more about how the raid backup on the pool cache works?

 

I have 2x 2tb SSDs and I could either: 

1 - Use the raid pool setting to mirror them so cache is backed up live. 2tb usable. 

2 - Use them as independent Cache pools and mirror to something else. 4tb usable.

3 - I could also run a script to backup the 2x cache drives onto the array at a specific time each day. 4tb usable.

 

- So my question is how is the speed of the raid mirror affected by drive speed?

- For example what If I use an non ssd drive for the caches mirror?

- How would the data be handled at a slower write speed?

- I'm guess you can only mirror from a single drive.

- Can it mirror to a usb drive?

 

Thanks

Edited August 30, 20223 yr by dopeytree

3 hours ago, dopeytree said:

mirror them so cache is backed up live

mirror is NOT backup.

 

Backups can be restored to fix things like file corruption and accidental deletion.

 

Mirror keeps the files identical in realtime, so if a file is deleted, it's gone everywhere.

 

mirror is NOT backup.

 

mirrors perform best with identical drives, but can be forced to use vastly different capacities and speeds, typically you will be restricted to the limits of the slower and smaller of the disparate drives.

So would you suggest btrfs snapshots as a backup strategy of the cache drives?