Как создавали СХД для СВ NumaTech

mdadm lvm numatech bcache

1) Create soft RAID 

# mdadm create --verbose /dev/md0  --level=10 --raid-devices 6 /dev/sdb /dev/sdc ... /dev/sdg
# cat /proc/mdstat

2) Add cache device bcache 

# modinfo bcache
# rpm -Uhv bcache-utils-xxxxx.rpm

Make md0 as backing device
# make-bcache -B /dev/md0
Make sdh as cache device
# make-bcache -C /dev/sdh
# make-bcache --block 4k --bucket 2M -C /dev/sdh
find its cache set UUID,
# bcache-super-show /dev/sdh | grep cset.uuid
# echo cset.uuid > /sys/block/bcache0/bcache/attach
Set cache policy for bcache (writeback - faster, writetrue - safety)
# echo writeback > /sys/block/bcache0/bcache/cache_mode
# mkinitcpio -p linux

3) Add volumes 

# modprobe raid1
# modprobe raid5
# modprobe raid10
# modprobe dm-mod
# vgcreate data /dev/bcache0
# vgdisplay
# lvcreate -L 100G  data -n iscsi_slice

4) Create filesystem 

# mkfs.ext4 /dev/data/p0

5) update initramfs 

# dracut -d bcache --force