Choosing mq-deadline over deadline offers a small performance win.
Multiqueue IO schedulers are not enabled by default in Ubuntu 18.04 - they become
the default in later versions of the Linux kernel.
If your host install process does not already enable MQ then you can use this
playbook to enable MQ; the playbook changes Grub config, and requires a
reboot for effect. You can see whether mq-deadline is available using
cat /sys/block/sda/queue/scheduler (substituting sda for your devices) - if it does not appear in the available list then consider enabling it.
Note that this playbook simply enables MQ IO scheduling - the selection
of mq-deadline is performed in ais_host_config_common.yml.
$ ansible-playbook -i hosts.ini ais_enble_multiqueue.yml -e ais_hosts=aisWe need only apply this against nodes that will host AIStore target nodes.
The playbook notes that a reboot is required but does not initiate reboot.