===Bcache===
The RAID5 array is set up and mounted as /bulk. We need to add the cache on the m.2 drive. Begin by installing bcache:
apt-get install bcache-tools
It was already installed and the newest version
See what we have:
fdisk -l
This gives us:
*/dev/nvme0n1p1 m.2
*/dev/sda RAID disk
*/dev/sdb RAID disk
*/dev/sdc RAID disk
*/dev/md0 RAID array
*/dev/sdd 870
The m.2 is not mounted. This can be seen by checking (or mount or df):
lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 3.7T 0 disk
└─sda1 8:1 0 3.7T 0 part
└─md0 9:0 0 7.3T 0 raid5 /bulk
sdb 8:16 0 3.7T 0 disk
└─sdb1 8:17 0 3.7T 0 part
└─md0 9:0 0 7.3T 0 raid5 /bulk
sdc 8:32 0 3.7T 0 disk
└─sdc1 8:33 0 3.7T 0 part
└─md0 9:0 0 7.3T 0 raid5 /bulk
sdd 8:48 0 465.8G 0 disk
└─sdd1 8:49 0 465.8G 0 part /
sr0 11:0 1 1024M 0 rom
nvme0n1 259:0 0 465.8G 0 disk
└─nvme0n1p1 259:1 0 465.8G 0 part
===Dev Tools===