利用udev设置一个磁盘的scheduler，
    新建一个/etc/udev/rules.d/io_scheduler.rules，内容如下, “#”开始的为注释内容，仅供参考
    udevadm trigger —name-match=sda 生效，重启以后也有效。

    [root@zjx86r06n01 rules.d]# ll
    total 20
    -rw-r—r— 1 root root 76 May 29 14:45 05-udev-pp.rules
    -rw-r—r—. 1 root root 153 Feb 27 2017 60-ipath.rules
    -rw-r—r—. 1 root root 709 May 31 2017 70-persistent-ipoib.rules
    -rw-r—r— 1 root root 258 May 29 14:46 80-udev-pp-xio.rules
    -rw-r—r— 1 root root 380 May 29 14:39 io_scheduler.rules
    [root@zjx86r06n01 rules.d]# cat io_scheduler.rules
    ACTION==”add|change”, KERNEL==”emcpowera”, ATTR{queue/scheduler}=”deadline”
    ACTION==”add|change”, KERNEL==”emcpowerb”, ATTR{queue/scheduler}=”deadline”
    ACTION==”add|change”, KERNEL==”emcpowerc”, ATTR{queue/scheduler}=”deadline”
    ACTION==”add|change”, KERNEL==”emcpowerd”, ATTR{queue/scheduler}=”deadline”
    ACTION==”add|change”, KERNEL==”emcpowere”, ATTR{queue/scheduler}=”deadline”
    [root@zjx86r06n01 rules.d]#

    [root@zjx86r06n01 ~]#
    [root@zjx86r06n01 ~]# cat /sys/block/emcpowera/queue/scheduler
    noop [deadline] cfq
    [root@zjx86r06n01 ~]# cat /sys/block/emcpowerb/queue/scheduler
    noop [deadline] cfq
    [root@zjx86r06n01 ~]#

    https://blog.csdn.net/sinat_38723234/article/details/105134482