参考：Oracle Linux 7: Udev rule for ASM Cannot Place the ASM Disk in a Directory under /dev (Doc ID 2217951.1)

适用于:

Linux OS - Version Oracle Linux 7.0 and later

Oracle Cloud Infrastructure - Version N/A and later

Linux x86-64

现象：

asm磁盘配置在/dev/asm下，用以下的udev规则，但是主机重启后，asm磁盘没有创建在/dev/asm下。

使用规则 :

KERNEL=="emcpower*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="360060160da5031005e5c4dab3230e311", RUN+="/bin/sh -c 'mknod /dev/asm/ASP_DATA12C b $major $minor; chown oracle:oinstall /dev/asm/ASP_DATA12C; chmod 0660 /dev/asm/ASP_DATA12C'"

原因：

The udev rule is triggered but it fails to create the disk under /dev/asm because the directory asm is not present under /dev.

In OL7, the /dev is a tmpfs and generated dynamically when the system comes up and hence the asm directory is not present under /dev after a reboot.

Test case:

There is no directory /dev/asm

@ ~]# udevadm control --reload-rules

@ ~]# udevadm trigger --type=devices --action=change

@ ~]# ll /dev/asm/

total 0

brw-rw---- 1 oracle oinstall 8, 32 Oct 18 22:51 ASP_DATA12C

Check the udev Rules

@ ~]# cat /etc/udev/rules.d/99-oracle-asmdevices.rules

ACTION=="add|change", KERNEL=="sdc", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-1", RUN+="/bin/sh -c 'mknod /dev/asm/ASP_DATA12C b $major $minor; chown oracle:oinstall /dev/asm/ASP_DATA12C; chmod 0660 /dev/asm/ASP_DATA12C'"

@ ~]# udevadm control --reload-rules

@ ~]# udevadm trigger --type=devices --action=change'mknod /dev/asm/ASP_DATA12C b $major $minor

@ ~]# ll /dev/sdc

sdc sdc1

@ ~]# ll /dev/sdc1

brw-rw---- 1 root disk 8, 33 Oct 18 22:48 /dev/sdc1

Created 'asm' directory manually but after the reboot directory will be deleted

@ ~]# mkdir /dev/asm                                              <<<< Created Directory 'asm'

@ ~]# mknod /dev/asm/ASP_DATA12C b 8 33            <<<<<<< 8 33 are major and minor numbers .

@ ~]# udevadm control --reload-rules

@ ~]# udevadm trigger --type=devices --action=change

@ ~]# ll /dev/asm/

total 0

brw-r--r-- 1 root root 8, 33 Oct 18 22:50 ASP_DATA12C

But after the reboot this directory will be deleted .

解决：

The solution is to create the directory using the udev rule before the asm disk is created.

Add the line highlighted in Bold (/usr/bin/mkdir /dev/asm) :

~]#

vi /etc/udev/rules.d/96-asmmultipath.rules

ACTION=="add|change", KERNEL=="sdb", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="1ATA_VBOX_HARDDISK_VB4e42ee2e-c26ef95f", RUN+="/bin/sh -c '

/usr/bin/mkdir

/dev/asm; mknod /dev/asm/ASP_DATA12C b $major $minor; chown oracle:oinstall /dev/asm/ASP_DATA12C; chmod 0660 /dev/asm/ASP_DATA12C'"

Try to run udevadm 'reload' and 'trigger' command once the rule is set :

~]# udevadm control --reload-rules

~]# udevadm trigger --type=devices --action=change

Check by Rebooting the server and check if the directory are present .

~]#

ll /dev/asm/

total 0

brw-rw----. 1 oracle oinstall 8, 16 Oct 19 10:42 ASP_DATA12C

例子：

KERNEL=="sd*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="363c7843100ba123b43600d8200000080", RUN+="/bin/sh -c '/usr/bin/mkdir /dev/asm; mknod /dev/asm/ocr01 b 8 16; chown grid:asmadmin /dev/asm/ocr01; chmod 0660 /dev/asm/ocr01'"

KERNEL=="sd*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="363c7843100ba123b436039e900000081", RUN+="/bin/sh -c '/usr/bin/mkdir /dev/asm; mknod /dev/asm/ocr02 b 8 32; chown grid:asmadmin /dev/asm/ocr02; chmod 0660 /dev/asm/ocr02'"

KERNEL=="sd*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="363c7843100ba123b4360540300000082", RUN+="/bin/sh -c '/usr/bin/mkdir /dev/asm; mknod /dev/asm/ocr03 b 8 48; chown grid:asmadmin /dev/asm/ocr03; chmod 0660 /dev/asm/ocr03'"

KERNEL=="sd*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="363c7843100ba123b43606e9e00000083", RUN+="/bin/sh -c '/usr/bin/mkdir /dev/asm; mknod /dev/asm/data01 b 8 64; chown grid:asmadmin /dev/asm/data01; chmod 0660 /dev/asm/data01'"

KERNEL=="sd*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="363c7843100ba123b4360875b00000084", RUN+="/bin/sh -c '/usr/bin/mkdir /dev/asm; mknod /dev/asm/data02 b 8 80; chown grid:asmadmin /dev/asm/data02; chmod 0660 /dev/asm/data02'"

KERNEL=="sd*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="363c7843100ba123b4360c84500000087", RUN+="/bin/sh -c '/usr/bin/mkdir /dev/asm; mknod /dev/asm/data03 b 8 96; chown grid:asmadmin /dev/asm/data03; chmod 0660 /dev/asm/data03'"

KERNEL=="sd*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="363c7843100ba123b4360af1000000086", RUN+="/bin/sh -c '/usr/bin/mkdir /dev/asm; mknod /dev/asm/data04 b 8 112; chown grid:asmadmin /dev/asm/data04; chmod 0660 /dev/asm/data04'"

KERNEL=="sd*[!0-9]", ENV{DEVTYPE}=="disk", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d $devnode", RESULT=="363c7843100ba123b4360ea7600000088", RUN+="/bin/sh -c '/usr/bin/mkdir /dev/asm; mknod /dev/asm/fra01 b 8 128; chown grid:asmadmin /dev/asm/fra01; chmod 0660 /dev/asm/fra01'"