首先来简要的介绍下什么是udev,udev是Linux kernel 2.6系列的通用内核设备管理器,以守护进程的方式运行于Linux系统，并监听在新设备初始化或设备从系统中移除时，内核（通过netlink socket）所发出的uevent；简单点讲就是当有多块磁盘的时候，可以用udev来固定磁盘对应的设备名；之前在部署11g rac的时候都偏好使用asmlib，在最近一次的部署中asmlib出现了问题，而又没有时间去排错，因而采用udev部署，故而简单记录下udev的配置过程！
一：模拟共享盘阵，这里采用先划分lvm，再通过iscsi共享的方式来模拟
[root@db1 ~]# pvcreate /dev/sdb
Physical volume "/dev/sdb" successfully created
[root@db1 ~]# vgcreate data /dev/sdb
/dev/hdc: open failed: Read-only file system
/dev/cdrom: open failed: Read-only file system
Attempt to close device '/dev/cdrom' which is not open.
Volume group "data" successfully created
[root@db1 ~]# lvcreate -n crs1 -L 2G data
Logical volume "crs1" created
[root@db1 ~]# lvcreate -n crs2 -L 2G data
Logical volume "crs2" created
[root@db1 ~]# lvcreate -n crs3 -L 2G data
Logical volume "crs3" created
[root@db1 ~]# lvcreate -n data -L 10G data
Logical volume "data" created
[root@db1 ~]# lvcreate -n fra -L 10G data
Logical volume "fra" created
[root@db1 ~]# lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
crs1 data -wi-a- 2.00G
crs2 data -wi-a- 2.00G
crs3 data -wi-a- 2.00G
data data -wi-a- 10.00G
fra data -wi-a- 10.00G
[root@db1 ~]# service tgtd start
Starting SCSI target daemon: [ OK ]
[root@db1 ~]# cat iscsi.sh
tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.2012-07-04.com.yang.rac:crs1
tgtadm --lld iscsi --op new --mode target --tid 2 -T iqn.2012-07-04.com.yang.rac:crs2
tgtadm --lld iscsi --op new --mode target --tid 3 -T iqn.2012-07-04.com.yang.rac:crs3
tgtadm --lld iscsi --op new --mode target --tid 4 -T iqn.2012-07-04.com.yang.rac:data
tgtadm --lld iscsi --op new --mode target --tid 5 -T iqn.2012-07-04.com.yang.rac:fra
tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 1 -b /dev/data/crs1
tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 2 -b /dev/data/crs2
tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 3 -b /dev/data/crs3
tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 4 -b /dev/data/data
tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 5 -b /dev/data/fra
tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
tgtadm --lld iscsi --op bind --mode target --tid 2 -I ALL
tgtadm --lld iscsi --op bind --mode target --tid 3 -I ALL
tgtadm --lld iscsi --op bind --mode target --tid 4 -I ALL
tgtadm --lld iscsi --op bind --mode target --tid 5 -I ALL
[root@db1 ~]# tgtadm --lld iscsi -o show -m target
[root@db1 ~]# sh iscsi.sh
[root@db1 ~]# tgtadm --lld iscsi -o show -m target
Target 1: iqn.2012-07-04.com.yang.rac:crs1
System information:
Driver: iscsi
State: ready
I_T nexus information:
LUN information:
LUN: 0
Type: controller
SCSI ID: deadbeaf1:0
SCSI SN: beaf10
Size: 0 MB
Online: Yes
Removable media: No
Backing store: No backing store
LUN: 1
Type: disk
SCSI ID: deadbeaf1:1
SCSI SN: beaf11
Size: 2147 MB
Online: Yes
Removable media: No
Backing store: /dev/data/crs1
LUN: 2
Type: disk
SCSI ID: deadbeaf1:2
SCSI SN: beaf12
Size: 2147 MB
Online: Yes
Removable media: No
Backing store: /dev/data/crs2
LUN: 3
Type: disk
SCSI ID: deadbeaf1:3
SCSI SN: beaf13
Size: 2147 MB
Online: Yes
Removable media: No
Backing store: /dev/data/crs3
LUN: 4
Type: disk
SCSI ID: deadbeaf1:4
SCSI SN: beaf14
Size: 10737 MB
Online: Yes
Removable media: No
Backing store: /dev/data/data
LUN: 5
Type: disk
SCSI ID: deadbeaf1:5
SCSI SN: beaf15
Size: 10737 MB
Online: Yes
Removable media: No
Backing store: /dev/data/fra
Account information:
ACL information:
ALL
Target 2: iqn.2012-07-04.com.yang.rac:crs2
System information:
Driver: iscsi
State: ready
I_T nexus information:
LUN information:
LUN: 0
Type: controller
SCSI ID: deadbeaf2:0
SCSI SN: beaf20
Size: 0 MB
Online: Yes
Removable media: No
Backing store: No backing store
Account information:
ACL information:
Target 3: iqn.2012-07-04.com.yang.rac:crs3
System information:
Driver: iscsi
State: ready
I_T nexus information:
LUN information:
LUN: 0
Type: controller
SCSI ID: deadbeaf3:0
SCSI SN: beaf30
Size: 0 MB
Online: Yes
Removable media: No
Backing store: No backing store
Account information:
ACL information:
Target 4: iqn.2012-07-04.com.yang.rac:data
System information:
Driver: iscsi
State: ready
I_T nexus information:
LUN information:
LUN: 0
Type: controller
SCSI ID: deadbeaf4:0
SCSI SN: beaf40
Size: 0 MB
Online: Yes
Removable media: No
Backing store: No backing store
Account information:
ACL information:
Target 5: iqn.2012-07-04.com.yang.rac:fra
System information:
Driver: iscsi
State: ready
I_T nexus information:
LUN information:
LUN: 0
Type: controller
SCSI ID: deadbeaf5:0
SCSI SN: beaf50
Size: 0 MB
Online: Yes
Removable media: No
Backing store: No backing store
Account information:
ACL information:
二:在客户端上挂载前面模拟出的共享磁盘阵列
[root@db2 ~]# iscsiadm --mode discovery --type sendtargets --portal 192.168.123.10
192.168.123.10:3260,1 iqn.2012-07-04.com.yang.rac:fra
192.168.123.10:3260,1 iqn.2012-07-04.com.yang.rac:crs1
192.168.123.10:3260,1 iqn.2012-07-04.com.yang.rac:crs3
192.168.123.10:3260,1 iqn.2012-07-04.com.yang.rac:data
192.168.123.10:3260,1 iqn.2012-07-04.com.yang.rac:crs2
[root@db2 ~]# iscsiadm --mode node --targetname iqn.2012-07-04.com.yang.rac:crs1 --portal 192.168.123.10 --login
[root@db2 ~]# iscsiadm --mode node --targetname iqn.2012-07-04.com.yang.rac:crs2 --portal 192.168.123.10 --login
[root@db2 ~]# iscsiadm --mode node --targetname iqn.2012-07-04.com.yang.rac:crs3 --portal 192.168.123.10 --login
[root@db2 ~]# iscsiadm --mode node --targetname iqn.2012-07-04.com.yang.rac:data --portal 192.168.123.10 --login
[root@db2 ~]# iscsiadm --mode node --targetname iqn.2012-07-04.com.yang.rac:fra --portal 192.168.123.10 --login
[root@db2 ~]# fdisk -l
Disk /dev/sda: 85.8 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 523 4096575 82 Linux swap / Solaris
/dev/sda3 524 1044379682400 83 Linux
Disk /dev/sdb: 2147 MB, 2147483648 bytes
67 heads, 62 sectors/track, 1009 cylinders
Units = cylinders of 4154 * 512 = 2126848 bytes
Disk /dev/sdb doesn't contain a valid partition table
Disk /dev/sdc: 2147 MB, 2147483648 bytes
67 heads, 62 sectors/track, 1009 cylinders
Units = cylinders of 4154 * 512 = 2126848 bytes
Disk /dev/sdc doesn't contain a valid partition table
Disk /dev/sdd: 2147 MB, 2147483648 bytes
67 heads, 62 sectors/track, 1009 cylinders
Units = cylinders of 4154 * 512 = 2126848 bytes
Disk /dev/sdd doesn't contain a valid partition table
Disk /dev/sde: 10.7 GB, 10737418240 bytes
64 heads, 32 sectors/track, 10240 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Disk /dev/sde doesn't contain a valid partition table
Disk /dev/sdf: 10.7 GB, 10737418240 bytes
64 heads, 32 sectors/track, 10240 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Disk /dev/sdf doesn't contain a valid partition table
三：开始配置udev
[root@db2 ~]# uname -r //在本例中操作系统的版本位CentOS5.4 64bit
2.6.18-164.el5
[root@db2 ~]# lsb_release -a
LSB Version::core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch
Distributor ID: CentOS
Description:CentOS release 5.4 (Final)
Release:5.4
Codename: Final
[root@db2 ~]# rpm -qa |grep udev
udev-095-14.21.el5
[root@db2 ~]# ps -ef |grep udev
root 4646 1 0 10:14 ?00:00:00 /sbin/udevd -d
root 6023 3039 0 10:32 pts/000:00:00 grep udev
[root@db2 ~]# grep -v ^# /etc/udev/udev.conf |grep -v ^$
udev_log="err"
[root@db2 ~]# scsi_id -g -u -s /block/sdb
S_beaf11
[root@db2 ~]# scsi_id -g -u -s /block/sdc
S_beaf12
[root@db2 ~]# scsi_id -g -u -s /block/sdd
S_beaf13
[root@db2 ~]# scsi_id -g -u -s /block/sde
S_beaf14
[root@db2 ~]# scsi_id -g -u -s /block/sdf
S_beaf15
[root@db2 ~]# cat /etc/udev/rules.d/99-raw.rules
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="S_beaf11", NAME="asmdisk1", OWNER="grid",
GROUP="asmadmin", MODE="0660"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="S_beaf12", NAME="asmdisk2", OWNER="grid",
GROUP="asmadmin", MODE="0660"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="S_beaf13", NAME="asmdisk3", OWNER="grid",
GROUP="asmadmin", MODE="0660"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="S_beaf14", NAME="asmdisk4", OWNER="grid",
GROUP="asmadmin", MODE="0660"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="S_beaf15", NAME="asmdisk5", OWNER="grid",
GROUP="asmadmin", MODE="0660"
[root@db2 ~]# ll /dev/asm*
ls: /dev/asm*: No such file or directory
[root@db2 ~]# /sbin/udevcontrol reload_rules
[root@db2 ~]# /sbin/start_udev
Starting udev: [ OK ]
[root@db2 ~]# ll /dev/asm*
brw-rw---- 1 grid asmadmin 8, 16 Jul 4 12:05 /dev/asmdisk1
brw-rw---- 1 grid asmadmin 8, 32 Jul 4 12:05 /dev/asmdisk2
brw-rw---- 1 grid asmadmin 8, 48 Jul 4 12:05 /dev/asmdisk3
brw-rw---- 1 grid asmadmin 8, 64 Jul 4 12:05 /dev/asmdisk4
brw-rw---- 1 grid asmadmin 8, 80 Jul 4 12:05 /dev/asmdisk5
备注：
1：在vmware中，scsi_id -g -u -s /block/sdb默认是不会出现uuid的，需要修改vmx文件，添加disk.EnableUUID参数
2：/block/sdb实际上是个不存在的路径，实际绝对路径是/sys/block/sdb，但使用scsi_id命令的时候必须用/block/sdb路径。