SUSE Linux 10配置裸设备(raw devices)

裸设备，是没有经过格式化的分区或磁盘，也叫裸分区(原始分区)，不被Unix通过文件系统来读取的特殊字符设备。它由应用程序负责对它进行读写操作。不经过文件系统的缓冲，是不被操作系统直接管理的设备。由于跨过操作系统管理，使得I/O效率更高。

在基于SUSE Linux 10上安装Oracle 10g RAC的话，由于Oracle 10g 不支持将ocr与votingdisk 存放在ASM 磁盘中，因此，依然需要为其使用裸设备方式。SUSE Linux裸设备的配置与其他的Linux稍有差异，下面将具体描述。  www.ahlinux.com

1、先对磁盘进行分区，sdd如下面的方法炮制

#下面的示例中使用sdc和sdd来用作裸设备，一块用于ocr,一块用于votingdisk

www.ahlinux.com

bo2dbp:~ # fdisk /dev/sdc

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):

Value out of range.

Partition number (1-4):

Value out of range.

Partition number (1-4): 1

First cylinder (1-200, default 1):

Using default value 1

Last cylinder or +size or +sizeM or +sizeK (1-200, default 200):

Using default value 200

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Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

2、分区后的结果

bo2dbp:~ # fdisk -l /dev/sdc

Disk /dev/sdc: 209 MB, 209715200 bytes

64 heads, 32 sectors/track, 200 cylinders

Units = cylinders of 2048 * 512 = 1048576 bytes

Device Boot      Start         End      Blocks   Id  System

/dev/sdc1               1         200      204784   83  Linux

bo2dbp:~ # fdisk -l /dev/sdd

Disk /dev/sdd: 209 MB, 209715200 bytes

64 heads, 32 sectors/track, 200 cylinders

Units = cylinders of 2048 * 512 = 1048576 bytes

Device Boot      Start         End      Blocks   Id  System

/dev/sdd1               1         200      204784   83  Linux

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3、配置裸设备

bo2dbp:~ # vi /etc/raw

# /etc/raw

#

# sample configuration to bind raw devices

# to block devices

#

# The format of this file is:

# raw:

#

# example:

# ---------

# raw1:hdb1

#

# this means: bind /dev/raw/raw1 to /dev/hdb1

#

# ...

#Add new raw devices

raw1:sdc1

raw2:sdd1

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4、启动裸设备

bo2dbp:~ # rcraw start

bind /dev/raw/raw1 to /dev/sdc1...                                    done

bind /dev/raw/raw2 to /dev/sdd1...                                    done

5、配置裸设备随系统启动

bo2dbp:~ # chkconfig raw

raw  on

#修改裸设备的权限与所有者，尽管该操作会修改，但重启之后将失效。永久修改见第7点

bo2dbp:~ # chown oracle:dba /dev/raw/raw[1-2]

bo2dbp:~ # chmod 660 /dev/raw/raw[1-2]

6、测试裸设备

bo2dbp:~ # dd if=/dev/zero of=/dev/raw/raw1 bs=1024k count=200

dd: writing `/dev/raw/raw1': No space left on device

200+0 records in

199+0 records out

209698816 bytes (210 MB) copied, 2.59567 seconds, 80.8 MB/s

7、修改裸设备启动后权限及所有者

#使用root用户修改/etc/udev/rules.d/50-udev-default.rules,确保raw设备的权限GROUP="dba", MODE="660", OWNER="oracle"

#将其中包含KENREL=="raw"的记录修改为如下

KERNEL=="raw[0-9]*", SUBSYSTEM=="raw", NAME="raw/%k", GROUP="dba", MODE="640", OWNER="oracle"

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8、确认配置成功

#重启之后的状态

bo2dbp:~ # ls -hltr /dev/raw

total 0

crw-rw---- 1 root   disk 162, 0 Sep 19 10:22 rawctl

crw-rw---- 1 oracle dba  162, 1 Sep 19 10:22 raw1

crw-rw---- 1 oracle dba  162, 2 Sep 19 10:22 raw2

bo2dbs:~ # /usr/sbin/raw -qa

/dev/raw/raw1:  bound to major 8, minor 33

/dev/raw/raw2:  bound to major 8, minor 49