Users Guide

Table Of Contents

mdadm

Create software RAID on NVDIMM-Ns.

Say there are 6 devices, /dev/pmem0.. /dev/pmem5.

Create directory /mnt/md0 /mnt/md1 /mnt/md2 /mnt/md5 /mnt/md6.

$ mkdir -p /mnt/md0

Create RAID 0

$ mdadm --create --verbose /dev/md0 --level=0 --raid-devices=6 /dev/pmem0 /dev/pmem1

/dev/pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5

$ cat /proc/mdstat

$ mkfs.xfs /dev/md0

$ mount /dev/md0 /mnt/md0

$ lsblk

Before you unmount the device, Read/Write data into /mnt/md0

$ umount /dev/md0

$ mdadm --stop /dev/md0

$ mdadm --zero-superblock /dev/pmem0 /dev/pmem1 /dev/pmem2 /dev/pmem3 /dev/pmem4 /dev/

pmem5

$ lsblk

Creating RAID 1 is similar as above

$ mdadm --create --verbose /dev/md1 --level=1 --raid-devices=6 /dev/pmem0 /dev/pmem1

/dev/pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5

$ cat /proc/mdstat

$ mkfs.xfs /dev/md1

$ mount /dev/md1 /mnt/md1

$ lsblk

Before unmounting the device, Read/Write data into /mnt/md1

$ umount /dev/md1

$ mdadm --stop /dev/md1

$ mdadm --zero-superblock /dev/pmem0 /dev/pmem1 /dev/pmem2 /dev/pmem3 /dev/pmem4 /dev/

pmem5

$ lsblk

RAID 5/5/6/10 Volumes can be created in a similar way.

RHEL 7.6 features

Namespace creation

Starting from RHEL 7.6, ndctl utility is available natively.

NVDIMM-N modules that have FW 9324 are not visible in the OS as this firmware has label support. In other words,

namespaces do not get enumerated automatically and using ndctl, namespaces have to be created first before mounting a

file system and accessing them.

NOTE:

It is also recommended that an OS patch is installed first to ensure proper functionality of the ndctl utility for

creating namespaces. This patch can be downloaded here https://access.redhat.com/solutions/3920221.

Run through the commands below as a super user to create /dev/pmem devices.

To display DIMM list run:

● $ ndctl list -D

Linux