SSD Cache Number of partitions - Convert EXT4 --> Btrfs + Convert JBOD to Raid 5

[Nico]

Hi,

I have 3 questions please

1) What is the numbers of partitions when you want to active SSD cache ? Which choice is recommended and why please ?
2) I'd like to convert my ext4 in btrfs on my array, but i have this error message in putty, umount: /mnt/md1: target is busy.
What can i do to unmount the volume so i can convert it please ?
3) Is it possible to convert JBOD to Raid 5 ? I have enough space on my array to do so, but not sure it's possible.

Thx for your help

[TMzethar]

HI,
→1.Any partition is fine, and multiple partitions can be assigned to multiple volumes.
→2.It is recommended that you first use the fuser command to clean up processes that are occupying md1.
→3.its impossble now, you have to reconstruct the array.

[Nico]

→1.Any partition is fine, and multiple partitions can be assigned to multiple volumes.
--> Thx, I tried 1 cause i have only one volume but it doesn't work, when i restart the ssd cache is not enabled whereas it says everything went ok before rebooting... It's a Samsung SSD 860 Pro 256 Go... Any idea ?

→2.It is recommended that you first use the fuser command to clean up processes that are occupying md1.
--> I'll try that, thank you

→3.its impossble now, you have to reconstruct the array.
--> I was afraid it was impossible

Thanks for your help anyway