Anyone have any experience with running a cache pool with both an nvme drive and a sata iii drive? I want to add a bit of redundancy to my VMs & appdata and I am curious about having a 3.5gbps capable nvme drive paired with a 600mbps drive. Will the sata drive be the bottleneck and take the cache pool speed down to the slowest drive in the pool's level?

Anyone have any experience with running a cache pool with both an nvme drive and a sata iii drive? I want to add a bit of redundancy to my VMs & appdata and I am curious about having a 3.5gbps capable nvme drive paired with a 600mbps drive. Will the sata drive be the bottleneck and take the cache pool speed down to the slowest drive in the pool's level?

i would expect that is the behaviour you would get as writes would have to happen to both drives before your data is secure (although I must admit I have not personally tried mixing drive types in this way).    It would be interesting to know whether BTRFS has any special support for a pool of drives with widely faring performance characteristics.  If so directing all reads towards the SSD would be desirable, but I doubt if BTRFS is that clever.

At the moment BTFRS does not make any distinction between devices, so using the default RAID1 profile write speed is going to be limited by your slowest device, read speed by the actual device used for that specif file, it will alternate.

Thanks for the replies guys. Figured it would be limited by the slowest.