原文地址：

http://blog.itpub.net/21752515/viewspace-1063051/

linux磁碟重啟亂序問題處理

    最近到客戶那去巡檢時，客戶提到一個問題，他們的rac在重啟的時候，原來的sda1、sdb1、sdc1會對應變成sdd1、sde1、sdf1，由於他們使用的是碟符來繫結裸裝置，所以啟動後，經常要手動執行以下命令
[[email protected] ~]# raw /dev/raw/raw1 /dev/sda1 
[[email protected] ~]# raw /dev/raw/raw2 /dev/sdb1
[[email protected]

在瞭解了他們的情況後，我基本上明白是什麼原因，這種盤序錯亂，與linux對磁碟的掃描機制有關，所以我們只能從另一角度去規避這樣的問題，使用id號去繫結，這樣就沒有問題。在告訴他後，他同意我們對他原來的繫結方式進行修改，具體操作如下：

[[email protected] ~]# fdisk -l

Disk /dev/sdd: 429.4 GB, 429496729600 bytes
255 heads, 63 sectors/track, 52216 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1       52216   419424988+  83  Linux

Disk /dev/sde: 209 MB, 209715200 bytes
7 heads, 58 sectors/track, 1008 cylinders
Units = cylinders of 406 * 512 = 207872 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sde1               1        1008      204595   83  Linux

Disk /dev/sdf: 209 MB, 209715200 bytes
7 heads, 58 sectors/track, 1008 cylinders
Units = cylinders of 406 * 512 = 207872 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdf1               1        1008      204595   83  Linux

可以看到，剛重啟的節點1是sdd/sde/sdf
另一個節點的情況是：
[[email protected] ~]# fdisk -l

Disk /dev/sda: 429.4 GB, 429496729600 bytes
255 heads, 63 sectors/track, 52216 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1       52216   419424988+  83  Linux

Disk /dev/sdb: 209 MB, 209715200 bytes
7 heads, 58 sectors/track, 1008 cylinders
Units = cylinders of 406 * 512 = 207872 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        1008      204595   83  Linux

Disk /dev/sdc: 209 MB, 209715200 bytes
7 heads, 58 sectors/track, 1008 cylinders
Units = cylinders of 406 * 512 = 207872 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1        1008      204595   83  Linux

分別在兩臺機子上執行如下命令：
[[email protected] ~] scsi_id -g -s /block/sda
360080e500017ff06000004054c47bd4a
[[email protected] ~] scsi_id -g -s /block/sdb
360080e500017fdd8000004c74c6344ef
[[email protected] ~] scsi_id -g -s /block/sdc
360080e500017ff060000044f4c63446e
[[email protected] ~] scsi_id -g -s /block/sdd
360080e500017ff06000004054c47bd4a
[[email protected] ~] scsi_id -g -s /block/sde
360080e500017fdd8000004c74c6344ef
[[email protected] ~] scsi_id -g -s /block/sdf
360080e500017ff060000044f4c63446e

能過對比，可以看到sda與sdd，sdb與sde，sdc與sdf是對應用的，所以我們啟用udev，通過繫結id來規避這個問題！

[[email protected] ~]# cd /etc/udev/rules.d/
[[email protected] rules.d]# ls -a
.                    50-udev.rules     60-pcmcia.rules         61-uinput-wacom.rules  90-hal.rules
..                   51-hotplug.rules  60-raw.rules            85-pcscd_ccid.rules    95-pam-console.rules
05-udev-early.rules  60-libsane.rules  60-wacom.rules          90-alsa.rules          98-kexec.rules
40-multipath.rules   60-net.rules      61-uinput-stddev.rules  90-dm.rules            bluetooth.rules
[[email protected] rules.d]# vi 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.
ACTION=="add", KERNEL=="sd*1", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="360080e500017ff060000044f4c63446e", RUN+="/bin/raw /dev/raw/raw1 %N"
ACTION=="add", KERNEL=="sd*1", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="360080e500017fdd8000004c74c6344ef", RUN+="/bin/raw /dev/raw/raw2 %N"
ACTION=="add", KERNEL=="sd*1", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="360080e500017ff06000004054c47bd4a", RUN+="/bin/raw /dev/raw/raw3 %N"
KERNEL=="raw[1-3]", OWNER="oracle", GROUP="dba", MODE="660"
[[email protected] rules.d]# start_udev 
 Starting udev: [  OK  ]
[[email protected] rules.d]#
[[email protected] rules.d]# raw -qa
/dev/raw/raw1:  bound to major 8, minor 81
/dev/raw/raw2:  bound to major 8, minor 65
/dev/raw/raw3:  bound to major 8, minor 49

同理，在另一臺機，也進行同樣的操作。

經過如上操作後，所有問題都解決了，不管怎麼重啟都不會有問題！