$ cat /proc/partitions |grep -e sd[c,d] -e nvm 259 0 244198584 nvme0n1 259 2 244197543 nvme0n1p1 8 32 6836191232 sdc 8 33 244197544 sdc1 8 48 6836191232 sdd 8 49 244197544 sdd1 $ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sdd1[1] sdc1[0] 244065408 blocks super 1.2 [2/2] [UU] bitmap: 1/2 pages [4KB], 65536KB chunk ** unused devices: $ cat /proc/partitions |grep -e sd[c,d] 8 48 6836191232 sdd 8 49 244197544 sdd1 8 50 2097152 sdd2 8 32 6836191232 sdc 8 33 244197544 sdc1 8 34 2097152 sdc2 $ git clone https://github.com/pkoutoupis/rapiddisk.git $ cd rapiddisk/ $ make $ sudo make install $ sudo modprobe rapiddisk $ sudo modprobe rapiddisk-cache $ lsmod|grep rapiddisk rapiddisk_cache 20480 0 rapiddisk 20480 0 $ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sdc2[1](W) rd0[0] 2094080 blocks super 1.2 [2/2] [UU] ** unused devices: $ sudo rapiddisk --attach 2048 rapiddisk 6.0 Copyright 2011 - 2019 Petros Koutoupis Attached device rd0 of size 2048 Mbytes $ sudo rapiddisk --list rapiddisk 6.0 Copyright 2011 - 2019 Petros Koutoupis List of RapidDisk device(s): RapidDisk Device 1: rd0 Size (KB): 2097152 List of RapidDisk-Cache mapping(s): None $ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sdc2[1](W) rd0[0] 2094080 blocks super 1.2 [2/2] [UU] ** unused devices: