The listed devices in the Node  column having the same Namespace id are the paths to a FlashSystem 900 volume. They are also seen in the multipath  listing. Example 5-25 shows the multipath entries for Namespace id 33. 

# multipath -ll /dev/dm-3 NVME_LP__0 (eui.20446f362044000000507600200000d8) dm-3 NVME,FlashSystem-9840 size=2.0T features='0' hwhandler='0' wp=rw `-+- policy='queue-length 0' prio=0 status=active |- 0:24632:1:33 nvme0n1 259:0 active undef running |- 1:8239:1:33 nvme1n1 259:2 active undef running |- 4:24634:1:33 nvme4n1 259:4 active undef running `- 5:8240:1:33 nvme5n1 259:6 active undef running 

## Enabling multi-queue for NVMe on SUSE 15 

Multi-queue NVMe I/O scheduling can be activated on SLES 15 using the grand unified bootloader (grub) blq-mq  parameter, as shown in Example 5-26. 

## Add “dm_mod.use_blk_mq=y” at the end of the GRUB_CMDLINE_LINUX_DEFAULT ## in /etc/default/grub ## Example line GRUB_CMDLINE_LINUX_DEFAULT ="<original values> dm_mod.use_blk_mq=y " ## build the new grub configuration: # grub2-mkconfig -o /boot/grub2/grub.cfg ## reboot the system using the new new grub parameter # reboot ## check for device mapper multi-queue setting: # multipath -l /dev/mapper/NVME_LP__1 NVME_LP__0 (eui.20446f362044000000507600200000d8) dm-1 NVME,FlashSystem-9840 size=2.0T features='2 queue_mode mq ' hwhandler='0' wp=rw 

This multi-queue setting improves the maximum number of IOPS and reduces the latency when using NVMe device mapper multipathing. 

