今天在搭建RAC的时候，使用udev方式来创建ASM磁盘，执行/sbin/scsi_id命令不知道啥原因,死活获取不到UUID,执行结果啥也不显示。

[root@seiang2 ~]# scsi_id -u -g

/dev/sdb

没有uuid貌似没法配置udev

rules文件，通过查阅相关资料，通过如下两种方式实现的,通过udevinfo(6版本操作系统udevadm取代了udevinfo)命令获取分区的信息,可以利用分区中的这2项信息SYSFS{start}=="63"和SYSFS{size}=="16771797"(6版本变为ATTR{start}=="4241160"和ATTR{size}=="2120580")来代替uuid唯一标识这个设备；

实验环境：

操作系统：Redhat5.5Hostname：seiang2.comsys.com

操作系统：Redhat6.4Hostname：test.comsys.com

目录

一、使用udevinfo/udevadm获取分区的唯一标识

二、使用裸设备创建asm

一、使用udevinfo/udevadm获取分区的唯一标识

新增加一块磁盘，并对它进行分区，分区之后通过udevinfo/udevadm命令来获取分区的唯一标识；

Redhat5版本

[root@seiang2

~]# ll /sbin/udev*

-rwxr-xr-x

1 root root  15176 May  5  2009

/sbin/udevcontrol

-rwxr-xr-x

1 root root  61864 May  5  2009

/sbin/udevd

-rwxr-xr-x

1 root root 899928 May  5  2009 /sbin/udevd.static

-rwxr-xr-x

1 root root  23680 May  5  2009

/sbin/udevsettle

-rwxr-xr-x

1 root root  24144 May  5  2009

/sbin/udevtrigger

[root@seiang2

~]# cd

/sys/block/sdb

[root@seiang2

~]# udevinfo -a

-p /sys/block/sdb

Udevinfo

starts with the device specified by the devpath and then

walks

up the chain of parent devices. It prints for every device

found,

all possible attributes in the udev rules key format.

A

rule to match, can be composed by the attributes of the device

and

the attributes from one single parent device.

looking at device '/block/sdb':

KERNEL=="sdb"

SUBSYSTEM=="block"

SYSFS{stat}=="      63

93     1248       19

0        0        0

0        0       19

19"

SYSFS{size}=="10485760"

SYSFS{removable}=="0"

SYSFS{range}=="16"

SYSFS{dev}=="8:16"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1/target1:0:0/1:0:0:0':

ID=="1:0:0:0"

BUS=="scsi"

DRIVER=="sd"

SYSFS{dh_state}=="detached"

SYSFS{ioerr_cnt}=="0x0"

SYSFS{iodone_cnt}=="0x51"

SYSFS{iorequest_cnt}=="0x51"

SYSFS{iocounterbits}=="32"

SYSFS{timeout}=="60"

SYSFS{state}=="running"

SYSFS{rev}=="1.0 "

SYSFS{model}=="VBOX HARDDISK   "

SYSFS{vendor}=="ATA     "

SYSFS{scsi_level}=="6"

SYSFS{type}=="0"

SYSFS{queue_type}=="simple"

SYSFS{queue_depth}=="31"

SYSFS{device_blocked}=="0"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1/target1:0:0':

ID=="target1:0:0"

BUS==""

DRIVER==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1':

ID=="host1"

BUS==""

DRIVER==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0':

ID=="0000:00:0d.0"

BUS=="pci"

DRIVER=="ahci"

SYSFS{broken_parity_status}=="0"

SYSFS{enable}=="1"

SYSFS{modalias}=="pci:v00008086d00002829sv00000000sd00000000bc01sc06i01"

SYSFS{local_cpus}=="00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000"

SYSFS{irq}=="177"

SYSFS{class}=="0x010601"

SYSFS{subsystem_device}=="0x0000"

SYSFS{subsystem_vendor}=="0x0000"

SYSFS{device}=="0x2829"

SYSFS{vendor}=="0x8086"

looking at parent device '/devices/pci0000:00':

ID=="pci0000:00"

BUS==""

DRIVER==""

[root@seiang2

~]# fdisk

/dev/sdb

Device

contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel

Building

a new DOS disklabel. Changes will remain in memory only,

until

you decide to write them. After that, of course, the previous

content

won't be recoverable.

Warning:

invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command

(m for help): n

Command

action

e

extended

p

primary partition (1-4)

p

Partition

number (1-4): 1

First

cylinder (1-652, default 1):

Using

default value 1

Last

cylinder or +size or +sizeM or +sizeK (1-652, default 652): +1G

Command

(m for help): n

Command

action

e

extended

p

primary partition (1-4)

p

Partition

number (1-4): 2

First

cylinder (124-652, default 124):

Using

default value 124

Last

cylinder or +size or +sizeM or +sizeK (124-652, default 652): +1G

Command

(m for help): n

Command

action

e

extended

p

primary partition (1-4)

p

Partition

number (1-4): 3

First

cylinder (126-652, default 126):

Using

default value 126

Last

cylinder or +size or +sizeM or +sizeK (126-652, default 652): +1G

Command

(m for help): p

Disk

/dev/sdb: 5368 MB, 5368709120 bytes

255

heads, 63 sectors/track, 652 cylinders

Units

= cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks

Id  System

/dev/sdb1               1         123      987966

83  Linux

/dev/sdb2             124         125       16065

83  Linux

/dev/sdb3             126         248      987997+

83  Linux

Command

(m for help): w

The

partition table has been altered!

Calling

ioctl() to re-read partition table.

Syncing

disks.

[root@seiang2

~]# ll /dev/sdb*

brw-r-----

1 root disk 8, 16 Jul 20 02:57 /dev/sdb

brw-r-----

1 root disk 8, 17 Jul 20 02:57 /dev/sdb1

brw-r-----

1 root disk 8, 18 Jul 20 02:57 /dev/sdb2

brw-r-----

1 root disk 8, 19 Jul 20 02:57 /dev/sdb3

使用udevinfo命令查看详细的分区信息

[root@seiang2

~]#udevinfo -a

-p /sys/block/sdb/sdb1

Udevinfo

starts with the device specified by the devpath and then

walks

up the chain of parent devices. It prints for every device

found,

all possible attributes in the udev rules key format.

A

rule to match, can be composed by the attributes of the device

and

the attributes from one single parent device.

looking at device '/block/sdb/sdb1':

KERNEL=="sdb1"

SUBSYSTEM=="block"

SYSFS{stat}=="      31

67      392       19

0        0        0

0        0       17

19"

SYSFS{size}=="1975932"

SYSFS{start}=="63"

SYSFS{dev}=="8:17"

looking at parent device '/block/sdb':

ID=="sdb"

BUS=="block"

DRIVER==""

SYSFS{stat}=="     196

575     3152       94

1        0        8

2        0       71

96"

SYSFS{size}=="10485760"

SYSFS{removable}=="0"

SYSFS{range}=="16"

SYSFS{dev}=="8:16"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1/target1:0:0/1:0:0:0':

ID=="1:0:0:0"

BUS=="scsi"

DRIVER=="sd"

SYSFS{dh_state}=="detached"

SYSFS{ioerr_cnt}=="0x0"

SYSFS{iodone_cnt}=="0xe1"

SYSFS{iorequest_cnt}=="0xe1"

SYSFS{iocounterbits}=="32"

SYSFS{timeout}=="60"

SYSFS{state}=="running"

SYSFS{rev}=="1.0 "

SYSFS{model}=="VBOX HARDDISK   "

SYSFS{vendor}=="ATA     "

SYSFS{scsi_level}=="6"

SYSFS{type}=="0"

SYSFS{queue_type}=="simple"

SYSFS{queue_depth}=="31"

SYSFS{device_blocked}=="0"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1/target1:0:0':

ID=="target1:0:0"

BUS==""

DRIVER==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1':

ID=="host1"

BUS==""

DRIVER==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0':

ID=="0000:00:0d.0"

BUS=="pci"

DRIVER=="ahci"

SYSFS{broken_parity_status}=="0"

SYSFS{enable}=="1"

SYSFS{modalias}=="pci:v00008086d00002829sv00000000sd00000000bc01sc06i01"

SYSFS{local_cpus}=="00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000"

SYSFS{irq}=="177"

SYSFS{class}=="0x010601"

SYSFS{subsystem_device}=="0x0000"

SYSFS{subsystem_vendor}=="0x0000"

SYSFS{device}=="0x2829"

SYSFS{vendor}=="0x8086"

looking at parent device

'/devices/pci0000:00':

ID=="pci0000:00"

BUS==""

DRIVER==""

[root@seiang2

rules.d]#udevinfo -a -p /sys/block/sdb/sdb3/

Udevinfo

starts with the device specified by the devpath and then

walks

up the chain of parent devices. It prints for every device

found,

all possible attributes in the udev rules key format.

A

rule to match, can be composed by the attributes of the device

and

the attributes from one single parent device.

looking

at device '/block/sdb/sdb3':

KERNEL=="sdb3"

SUBSYSTEM=="block"

SYSFS{stat}=="      27

355      382       31

0        0        0

0        0       31

31"

SYSFS{size}=="1975995"

SYSFS{start}=="2008125"

SYSFS{dev}=="8:19"

looking at parent device '/block/sdb':

ID=="sdb"

BUS=="block"

DRIVER==""

SYSFS{stat}=="     395

1754     5700      383

2        0       16

8        0      242

391"

SYSFS{size}=="10485760"

SYSFS{removable}=="0"

SYSFS{range}=="16"

SYSFS{dev}=="8:16"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1/target1:0:0/1:0:0:0':

ID=="1:0:0:0"

BUS=="scsi"

DRIVER=="sd"

SYSFS{dh_state}=="detached"

SYSFS{ioerr_cnt}=="0x0"

SYSFS{iodone_cnt}=="0x1b3"

SYSFS{iorequest_cnt}=="0x1b3"

SYSFS{iocounterbits}=="32"

SYSFS{timeout}=="60"

SYSFS{state}=="running"

SYSFS{rev}=="1.0 "

SYSFS{model}=="VBOX HARDDISK   "

SYSFS{vendor}=="ATA     "

SYSFS{scsi_level}=="6"

SYSFS{type}=="0"

SYSFS{queue_type}=="simple"

SYSFS{queue_depth}=="31"

SYSFS{device_blocked}=="0"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1/target1:0:0':

ID=="target1:0:0"

BUS==""

DRIVER==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host1':

ID=="host1"

BUS==""

DRIVER==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0':

ID=="0000:00:0d.0"

BUS=="pci"

DRIVER=="ahci"

SYSFS{broken_parity_status}=="0"

SYSFS{enable}=="1"

SYSFS{modalias}=="pci:v00008086d00002829sv00000000sd00000000bc01sc06i01"

SYSFS{local_cpus}=="00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000"

SYSFS{irq}=="177"

SYSFS{class}=="0x010601"

SYSFS{subsystem_device}=="0x0000"

SYSFS{subsystem_vendor}=="0x0000"

SYSFS{device}=="0x2829"

SYSFS{vendor}=="0x8086"

looking at parent device

'/devices/pci0000:00':

ID=="pci0000:00"

BUS==""

DRIVER==""

编辑udev的rule文件

[root@seiang2

~]# cd

/etc/udev/rules.d/

[root@seiang2

rules.d]# vim

99-oracle-asmdevices.rules

KERNEL=="sdb1",

SUBSYSTEM=="block", SYSFS{size}=="1975932", SYSFS{start}=="63",

OWNER="grid",NAME="asmdisk-data1",

GROUP="asmadmin", MODE="0660"

KERNEL=="sdb3",

SUBSYSTEM=="block", SYSFS{size}=="1975995", SYSFS{start}=="2008125",

OWNER="grid",NAME="asmdisk-data2",

GROUP="asmadmin", MODE="0660"

编辑rule文件之后可以使用udevtest测试udev对设备的管理,命名,链接以及权限的设置情况

[root@seiang2

rules.d]# udevtest

/block/sdb

main:

looking at device '/block/sdb' from subsystem 'block'

run_program:

'/lib/udev/usb_id -x'

run_program:

'/lib/udev/usb_id' returned with status 1

run_program:

'/lib/udev/scsi_id -g -x -s /block/sdb -d /dev/.tmp-8-16'

run_program:

'/lib/udev/scsi_id' (stdout) 'ID_VENDOR=ATA'

run_program:

'/lib/udev/scsi_id' (stdout) 'ID_MODEL=VBOX_HARDDISK'

run_program:

'/lib/udev/scsi_id' (stdout) 'ID_REVISION=1.0'

run_program:

'/lib/udev/scsi_id' (stdout) 'ID_SERIAL=SATA_VBOX_HARDDISK_VBda65d90d-e2055c6a'

run_program:

'/lib/udev/scsi_id' (stdout) 'ID_TYPE=disk'

run_program:

'/lib/udev/scsi_id' (stdout) 'ID_BUS=scsi'

run_program:

'/lib/udev/scsi_id' returned with status 0

udev_rules_get_name:

add symlink 'disk/by-id/scsi-SATA_VBOX_HARDDISK_VBda65d90d-e2055c6a'

run_program:

'/lib/udev/path_id /block/sdb'

run_program:

'/lib/udev/path_id' (stdout) 'ID_PATH=pci-0000:00:0d.0-scsi-1:0:0:0'

run_program:

'/lib/udev/path_id' returned with status 0

udev_rules_get_name:

add symlink 'disk/by-path/pci-0000:00:0d.0-scsi-1:0:0:0'

run_program:

'/lib/udev/vol_id --export /dev/.tmp-8-16'

run_program:

'/lib/udev/vol_id' returned with status 4

run_program:

'/lib/udev/edd_id --export /dev/.tmp-8-16'

run_program:

'/lib/udev/edd_id' (stderr) 'no kernel EDD support'

run_program:

'/lib/udev/edd_id' returned with status 2

udev_rules_get_name:

no node name set, will use kernel name 'sdb'

udev_device_event:

device '/block/sdb' already in database, validate currently present symlinks

udev_node_add:

creating device node '/dev/sdb', major = '8', minor = '16', mode = '0640', uid

= '0', gid = '6'

udev_node_add:

creating symlink '/dev/disk/by-id/scsi-SATA_VBOX_HARDDISK_VBda65d90d-e2055c6a'

to '../../sdb'

udev_node_add:

creating symlink '/dev/disk/by-path/pci-0000:00:0d.0-scsi-1:0:0:0' to

'../../sdb'

main:

run: 'socket:/org/kernel/udev/monitor'

main:

run: '/lib/udev/udev_run_devd'

main:

run: 'socket:/org/freedesktop/hal/udev_event'

main:

run: '/sbin/pam_console_apply /dev/sdb /dev/disk/by-id/scsi-SATA_VBOX_HARDDISK_VBda65d90d-e2055c6a

/dev/disk/by-path/pci-0000:00:0d.0-scsi-1:0:0:0'

重新启动udev,在启动之前首先使用命令udevcontrol重新装载rules(此步骤可以省略)

[root@seiang2

rules.d]# udevcontrol

reload_rules

[root@seiang2

rules.d]# start_udev

Starting

udev:

[  OK  ]

[root@seiang2

rules.d]# ll

/dev/asm*

brw-rw----

1 grid asmadmin 8, 17 Jul 20 03:09 /dev/asmdisk-data1

brw-rw----

1 grid asmadmin 8, 19 Jul 20 03:09 /dev/asmdisk-data2

[root@seiang2

rules.d]#

Redhat6版本

[root@test

rules.d]# udevadm

info -a -p /sys/block/sdb/sdb2

Udevadm

info starts with the device specified by the devpath and then

walks

up the chain of parent devices. It prints for every device

found,

all possible attributes in the udev rules key format.

A

rule to match, can be composed by the attributes of the device

and

the attributes from one single parent device.

looking at device

'/devices/pci0000:00/0000:00:0d.0/host3/target3:0:0/3:0:0:0/block/sdb/sdb2':

KERNEL=="sdb2"

SUBSYSTEM=="block"

DRIVER==""

ATTR{partition}=="2"

ATTR{start}=="2120580"

ATTR{size}=="2120580"

ATTR{alignment_offset}=="0"

ATTR{discard_alignment}=="0"

ATTR{stat}=="     238

84     1288      247

0        0        0

0        0      232

247"

ATTR{inflight}=="       0

0"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host3/target3:0:0/3:0:0:0/block/sdb':

KERNELS=="sdb"

SUBSYSTEMS=="block"

DRIVERS==""

ATTRS{range}=="16"

ATTRS{ext_range}=="256"

ATTRS{removable}=="0"

ATTRS{ro}=="0"

ATTRS{size}=="10485760"

ATTRS{alignment_offset}=="0"

ATTRS{discard_alignment}=="0"

ATTRS{capability}=="52"

ATTRS{stat}=="    2082

4734    15818     2580

640    98980    99628

48250        0     2549

50830"

ATTRS{inflight}=="       0

0"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host3/target3:0:0/3:0:0:0':

KERNELS=="3:0:0:0"

SUBSYSTEMS=="scsi"

DRIVERS=="sd"

ATTRS{device_blocked}=="0"

ATTRS{type}=="0"

ATTRS{scsi_level}=="6"

ATTRS{vendor}=="ATA     "

ATTRS{model}=="VBOX HARDDISK   "

ATTRS{rev}=="1.0 "

ATTRS{state}=="running"

ATTRS{timeout}=="30"

ATTRS{iocounterbits}=="32"

ATTRS{iorequest_cnt}=="0xb10"

ATTRS{iodone_cnt}=="0xb0e"

ATTRS{ioerr_cnt}=="0xf"

ATTRS{modalias}=="scsi:t-0x00"

ATTRS{evt_media_change}=="0"

ATTRS{dh_state}=="detached"

ATTRS{queue_depth}=="31"

ATTRS{queue_ramp_up_period}=="120000"

ATTRS{queue_type}=="simple"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host3/target3:0:0':

KERNELS=="target3:0:0"

SUBSYSTEMS=="scsi"

DRIVERS==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host3':

KERNELS=="host3"

SUBSYSTEMS=="scsi"

DRIVERS==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0':

KERNELS=="0000:00:0d.0"

SUBSYSTEMS=="pci"

DRIVERS=="ahci"

ATTRS{vendor}=="0x8086"

ATTRS{device}=="0x2829"

ATTRS{subsystem_vendor}=="0x0000"

ATTRS{subsystem_device}=="0x0000"

ATTRS{class}=="0x010601"

ATTRS{irq}=="21"

ATTRS{local_cpus}=="1"

ATTRS{local_cpulist}=="0"

ATTRS{modalias}=="pci:v00008086d00002829sv00000000sd00000000bc01sc06i01"

ATTRS{numa_node}=="-1"

ATTRS{enable}=="1"

ATTRS{broken_parity_status}=="0"

ATTRS{msi_bus}==""

looking at parent device

'/devices/pci0000:00':

KERNELS=="pci0000:00"

SUBSYSTEMS==""

DRIVERS==""

[root@test

rules.d]# udevadm

info -a -p /sys/block/sdb/sdb3

Udevadm

info starts with the device specified by the devpath and then

walks

up the chain of parent devices. It prints for every device

found,

all possible attributes in the udev rules key format.

A

rule to match, can be composed by the attributes of the device

and

the attributes from one single parent device.

looking at device

'/devices/pci0000:00/0000:00:0d.0/host3/target3:0:0/3:0:0:0/block/sdb/sdb3':

KERNEL=="sdb3"

SUBSYSTEM=="block"

DRIVER==""

ATTR{partition}=="3"

ATTR{start}=="4241160"

ATTR{size}=="2120580"

ATTR{alignment_offset}=="0"

ATTR{discard_alignment}=="0"

ATTR{stat}=="     200

122     1288      255

0        0        0

0        0      250

255"

ATTR{inflight}=="       0

0"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host3/target3:0:0/3:0:0:0/block/sdb':

KERNELS=="sdb"

SUBSYSTEMS=="block"

DRIVERS==""

ATTRS{range}=="16"

ATTRS{ext_range}=="256"

ATTRS{removable}=="0"

ATTRS{ro}=="0"

ATTRS{size}=="10485760"

ATTRS{alignment_offset}=="0"

ATTRS{discard_alignment}=="0"

ATTRS{capability}=="52"

ATTRS{stat}=="    2082

4734    15818     2580

640    98980    99628

48250        0     2549

50830"

ATTRS{inflight}=="       0

0"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host3/target3:0:0/3:0:0:0':

KERNELS=="3:0:0:0"

SUBSYSTEMS=="scsi"

DRIVERS=="sd"

ATTRS{device_blocked}=="0"

ATTRS{type}=="0"

ATTRS{scsi_level}=="6"

ATTRS{vendor}=="ATA     "

ATTRS{model}=="VBOX HARDDISK   "

ATTRS{rev}=="1.0 "

ATTRS{state}=="running"

ATTRS{timeout}=="30"

ATTRS{iocounterbits}=="32"

ATTRS{iorequest_cnt}=="0xb10"

ATTRS{iodone_cnt}=="0xb0e"

ATTRS{ioerr_cnt}=="0xf"

ATTRS{modalias}=="scsi:t-0x00"

ATTRS{evt_media_change}=="0"

ATTRS{dh_state}=="detached"

ATTRS{queue_depth}=="31"

ATTRS{queue_ramp_up_period}=="120000"

ATTRS{queue_type}=="simple"

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host3/target3:0:0':

KERNELS=="target3:0:0"

SUBSYSTEMS=="scsi"

DRIVERS==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0/host3':

KERNELS=="host3"

SUBSYSTEMS=="scsi"

DRIVERS==""

looking at parent device

'/devices/pci0000:00/0000:00:0d.0':

KERNELS=="0000:00:0d.0"

SUBSYSTEMS=="pci"

DRIVERS=="ahci"

ATTRS{vendor}=="0x8086"

ATTRS{device}=="0x2829"

ATTRS{subsystem_vendor}=="0x0000"

ATTRS{subsystem_device}=="0x0000"

ATTRS{class}=="0x010601"

ATTRS{irq}=="21"

ATTRS{local_cpus}=="1"

ATTRS{local_cpulist}=="0"

ATTRS{modalias}=="pci:v00008086d00002829sv00000000sd00000000bc01sc06i01"

ATTRS{numa_node}=="-1"

ATTRS{enable}=="1"

ATTRS{broken_parity_status}=="0"

ATTRS{msi_bus}==""

looking at parent device

'/devices/pci0000:00':

KERNELS=="pci0000:00"

SUBSYSTEMS==""

DRIVERS==""

[root@test

rules.d]# vim

99-oracle-asmdevices.rules

KERNEL=="sdb2",

SUBSYSTEM=="block", ATTR{size}=="2120580", ATTR{start}=="2120580",

OWNER="grid",NAME="asmdisk-data1",

GROUP="asmadmin", MODE="0660"

KERNEL=="sdb3",

SUBSYSTEM=="block", ATTR{size}=="2120580", ATTR{start}=="4241160",

OWNER="grid",NAME="asmdisk-data2",

GROUP="asmadmin", MODE="0660"

[root@test

rules.d]# start_udev

Starting

udev:

[  OK  ]

[root@test

rules.d]# ll

/dev/asm*

brw-rw----.

1 grid asmadmin 8, 18 Jul 20 15:57 /dev/asmdisk-data1

brw-rw----.

1 grid asmadmin 8, 19 Jul 20 15:57 /dev/asmdisk-data2

注意：从这里可以看到通过配置99-oracle-asmdevices.rules文件，创建出来的是块类型的设备

可以对比观察下面通过裸设备创建出来的设备类型

二、使用裸设备创建asm磁盘

新增加一块磁盘，并对其进行分区；

[root@seiang2

rules.d]# fdisk /dev/sdb

Command

(m for help): n

Command

action

e

extended

p

primary partition (1-4)

e

Selected

partition 4

First

cylinder (249-652, default 249):

Using

default value 249

Last

cylinder or +size or +sizeM or +sizeK (249-652, default 652):

Using

default value 652

Command

(m for help): n

First

cylinder (249-652, default 249):

Using

default value 249

Last

cylinder or +size or +sizeM or +sizeK (249-652, default 652): +1G

Command

(m for help): n

First

cylinder (372-652, default 372):

Using

default value 372

Last

cylinder or +size or +sizeM or +sizeK (372-652, default 652): +1G

Command

(m for help): w

The

partition table has been altered!

Calling

ioctl() to re-read partition table.

Syncing

disks.

[root@seiang2

rules.d]# fdisk

-l

Disk

/dev/sda: 16.1 GB, 16106127360 bytes

255

heads, 63 sectors/track, 1958 cylinders

Units

= cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks

Id  System

/dev/sda1   *

1          13      104391

83  Linux

/dev/sda2              14        1958

15623212+  8e  Linux LVM

Disk

/dev/sdb: 5368 MB, 5368709120 bytes

255

heads, 63 sectors/track, 652 cylinders

Units

= cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks

Id  System

/dev/sdb1               1         123      987966

83  Linux

/dev/sdb2             124         125       16065

83  Linux

/dev/sdb3             126         248      987997+

83  Linux

/dev/sdb4             249         652

3245130    5  Extended

/dev/sdb5             249         371      987966

83  Linux

/dev/sdb6             372         494      987966

83  Linux

配置裸设备映射，修改/etc/udev/rules.d/60-raw.rules文件

[root@seiang2

rules.d]# vim

60-raw.rules

ACTION=="add",

KERNEL=="/dev/sdb5", RUN+="/bin/raw /dev/raw/raw5 %N"

ACTION=="add",

ENV{MAJOR}=="8", ENV{MINOR}=="1", RUN+="/bin/raw

/dev/raw/raw5 %M %m"

ACTION=="add",

KERNEL=="/dev/sdb6", RUN+="/bin/raw /dev/raw/raw6 %N"

ACTION=="add",

ENV{MAJOR}=="8", ENV{MINOR}=="2", RUN+="/bin/raw

/dev/raw/raw6 %M %m"

ACTION=="add",

KERNEL=="raw5", OWNER="grid", GROUP="asmadmin",

MODE="0660"

ACTION=="add",

KERNEL=="raw6", OWNER="grid", GROUP="asmadmin",

MODE="0660"

重启udev服务，并查询raw

[root@seiang2

rules.d]# start_udev

Starting

udev:

[  OK  ]

[root@seiang2

rules.d]#raw

-qa

/dev/raw/raw5:  bound to major 8, minor 1

/dev/raw/raw6:  bound to major 8, minor 2

[root@seiang2

rules.d]# ll

/dev/raw*

crw-------

1 root root 162, 0 Jul 20 02:53 /dev/rawctl

/dev/raw:

total

0

crw-rw---- 1 grid

asmadmin 162, 5 Jul 20 03:31 raw5

crw-rw---- 1 grid

asmadmin 162, 6 Jul 20 03:31 raw6

注意：从这里可以看到通过配置60-raw.rules文件，创建出来的是字符类型的设备

这样配置之后，裸设备文件会自动映射到相应的分区设备文件，并设置正确的用户和组。

裸设备：也叫裸分区(原始分区)，是一种没有经过格式化，不被Unix/Linux通过文件系统来读取的特殊字符设备。裸设备可以绑定一个分区，也可以绑定一个磁盘。

字符设备：对字符设备的读写不需要通过OS的buffer。它不可被文件系统mount。

块设备：对块设备的读写需要通过OS的buffer，它可以被mount到文件系统中。

这个与linux的版本相关，在旧版本中，最多只可以有256个裸设备，Linux 4下做多可以绑定81Array2个裸设备。但是在linux下，最多只能有255个分区，所以，如果用裸设备绑定分区，最多只能绑定255个裸设备。如果是用lvm，则没有这个限制。

Linux下单个磁盘最多可以有15个分区。3个主分区 + 1个扩展分区 + 11个逻辑分区。

建议的分区方法是：先分3个主分区，第四个分区为扩展分区，然后在扩展分区中再分成11个逻辑分区。

注意:裸设备不要绑定在扩展分区上。linux下如果需要使用裸设备，则需要手工进行绑定，unix下则不用。

major和minor device

number

在unix/linux系统中，一切都是文件。所有硬盘、键盘等设备都用文件来代表，对应着/dev下面的文件。对于应用程序来说，可以像对待普通文件一样打开，关闭、读写这些设备文件。但是这种文件名，比如/dev/sda、/dev /raw/raw1都是用户空间名称，OS Kernel根本不知道这个名称指的是什么。在内核空间是通过major、minor device

number 来区分设备的。

major device number可以看作是设备驱动程序，被同一设备驱动程序管理的设备有相同的major device

number。这个数字实际是Kernel中device driver

table 的索引，这个表保存着不同设备驱动程序。而minor device

number用来代表被访问的具体设备。也就是说Kernel根据major device

number 找到设备驱动程序，然后再从minor device

number 获得设备位置等属性。所有这些major device

number 是已经预先分配好的。比如裸设备是162，scsi块设备是8

Redhat平台对raw设备的配置在redhat 5之后有了变化。在redhat 5之前，直接配置/etc/sysconfig/rawdevices件，通过/etc/init.d/rawdevices来管理raw设备的启动和关闭。在Redhat 5之后，原来的raw设备接口已经取消了，redhat 5中通过udev规则进行配置。 要配置，需要编辑/etc/udev/rules.d/60-raw.rules这个文件。

cat /etc/udev/rules.d/60-raw.rules

# Enter raw device bindings here.

#

# An example would be:

#   ACTION=="add", KERNEL=="sda",

RUN+="/bin/raw /dev/raw/raw1 %N"

# to bind /dev/raw/raw1 to /dev/sda, or

#   ACTION=="add", ENV{MAJOR}=="8",

ENV{MINOR}=="1", RUN+="/bin/raw /dev/raw/raw2 %M %m"

# to bind /dev/raw/raw2 to the device with major 8, minor 1.

其中

ACTION=="add", KERNEL="", RUN+="raw /dev/raw/rawX

%N"

配置设备名称，用你需要绑定的设备名称替换 (如：/dev/sda1)，X为裸设备号

主/次号码：

ACTION=="add", ENV{MAJOR}="A",

ENV{MINOR}="B", RUN+="raw /dev/raw/rawX %M %m"

"A" 和 "B" 是设备的主/次号码，X是系统使用的raw设备号码。

个人对redhat管理raw的过程理解为：在redhat 5中，是通过udev来管理raw设备的，而udev是通过 MAJOR和MINOR来识别 raw设备。故需要将设备号和裸设备号进行绑定，而主设备号和次设备号可以自行指定或者由系统自动分配。 根据red hat的官方文档中关于raw.rule的示例中说KERNEL==..或ENV{MAJOR}...只需要任意配置一个就可以，但有些网友经过试验，验证必须二者同时配置才可以。

如果有多个raw设备，可以写成：

ACTION=="add", KERNEL=="raw[1-4]",

OWNER="dave", GROUP="tianlesoftware", MODE="0660"

注意：在内核2.6.9-89.5AXS2之前使用/etc/sysconfig/rawdevices和/etc/udev/permissions.d/50-udev.permissions进行raw设备的配置和权限管理。在内核 2.6.18-128.7AXS3以后则使用了本文介绍的 /etc/udev/rules.d/60-raw.rules进行raw设备的管理

使用裸设备作为Oracle的数据文件的注意事项

1、一个裸设备只能放置一个数据文件

2、数据文件的大小不能超过裸设备的大小

如果是日志文件，则裸设备最大可用大小=裸设备对应分区大小 - 1 * 512 (保留一个redo lock)

如果是数据文件，则裸设备最大可用大小=裸设备对应分区大小 - 2 *

db_block_size(保留两个block)

为了简单起见，对所有的文件设置称比裸设备小1M即可。

3、数据文件最好不要设置称自动扩展，如果设置称自动扩展，一定要把maxsize设置设置为比裸设备小

4、linux下oracle不能直接把逻辑卷作为裸设备，也要进行绑定。unix下就不需要。

相关链接：

作者：SEian.G(苦练七十二变，笑对八十一难)

ITPUB：http://blog.itpub.net/31015730/

51CTO：http://seiang.blog.51cto.com/