oracle自从10g退出ASM之后，现在生产环境中使用ASM的场景越来越多。有时可能会发生对磁盘的误操作，导致ASM磁盘的损坏，这对数据库来说是致命的。如果有工具能查看磁盘是否是ASM使用的磁盘，这样会更方便，更安全。
如果一块磁盘用作ASM，那么Oracle就会在磁盘的头部表示出来，字符是ORCLDISK，包括Windows和所用Unix平台。可以通过od -N 128 -c <设备全路径>查看，这个命令是通用的，适用所用unix平台，当然aodu也可以实现。
注意：创建ASM磁盘后，想在使用，必须删除(通过asmca或命令行)，或者通过dd清除设备头部即可。
dd if=/dev/zero of=/dev/hdiskpower10 bs=1024 count=10
通过aodu查看
[root@ohs1 linux]# ./aodu
At Oracle Database Utility,Release 1.1.0 on Tue Jun 14 11:35:09 2016
Copyright (c) 2014, 2015, Robin.Han. All rights reserved.
http://ohsdba.cn
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Cell:186-9589-1286
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AODU>
AODU> asmdisk /dev/sdb1 The disk /dev/sdb1 still used by ASM. AODU> asmdisk /dev/sdb2 The disk /dev/sdb2 still used by ASM. AODU> asmdisk /dev/sdb11 The disk /dev/sdb11 still used by ASM. AODU> asmdisk /dev/sdb12 The disk /dev/sdb12 has been used by ASM. AODU> asmdisk /dev/sdb13 The disk /dev/sdb13 has not been used by ASM. AODU> asmdisk /dev/sdb14 The disk /dev/sdb14 has been used by ASM. AODU> asmdisk /dev/sdb15 The disk /dev/sdb15 still used by ASM. AODU> asmdisk /dev/sdb16 /dev/sdb16: Bad file descriptor AODU>
AIX是可以使用lquerypv查看，非常方便
$ lquerypv -h /dev/hdiskpower1
00000000 00000000 00000000 00000000 00000000 |................| 00000010 00000000 00000000 00000000 00000000 |................| 00000020 00000000 00000000 00000000 00000000 |................| 00000030 00000000 00000000 00000000 00000000 |................| 00000040 00000000 00000000 00000000 00000000 |................| 00000050 00000000 00000000 00000000 00000000 |................| 00000060 00000000 00000000 00000000 00000000 |................| 00000070 00000000 00000000 00000000 00000000 |................| 00000080 00000000 00000000 00000000 00000000 |................| 00000090 00000000 00000000 00000000 00000000 |................| 000000A0 00000000 00000000 00000000 00000000 |................| 000000B0 00000000 00000000 00000000 00000000 |................| 000000C0 00000000 00000000 00000000 00000000 |................| 000000D0 00000000 00000000 00000000 00000000 |................| 000000E0 00000000 00000000 00000000 00000000 |................| 000000F0 00000000 00000000 00000000 00000000 |................| $用作ASM后，可以看到
#lquerypv -h /dev/hdiskpower0 00000000 00820101 00000000 80000000 9FD017BD |................| 00000010 00000000 00000000 00000000 00000000 |................| 00000020 4F52434C 4449534B 00000000 00000000 |ORCLDISK........| 00000030 00000000 00000000 00000000 00000000 |................| 00000040 0B200000 00000203 53595354 454D4447 |. ......SYSTEMDG| 00000050 5F303030 30000000 00000000 00000000 |_0000...........| 00000060 00000000 00000000 53595354 454D4447 |........SYSTEMDG| 00000070 00000000 00000000 00000000 00000000 |................| 00000080 00000000 00000000 53595354 454D4447 |........SYSTEMDG| 00000090 5F303030 30000000 00000000 00000000 |_0000...........| 000000A0 00000000 00000000 00000000 00000000 |................| 000000B0 00000000 00000000 00000000 00000000 |................| 000000C0 00000000 00000000 01F81331 E1851000 |...........1....| 000000D0 01F81332 005A5C00 02001000 00100000 |...2.Z\.........| 000000E0 0001BC80 00001000 00000002 00000001 |................| 000000F0 00000002 00000002 00000000 00000000 |................| #
Linux上没有这个好用的工具，可以通过od查看
[root@ohs1 /]# od --read-bytes=128 --format=c /dev/sdb1
0000000 001 202 001 001 \0 \0 \0 \0 \0 \0 \0 200 310 ; U [ 0000020 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000040 O R C L D I S K A S M D I S K 1 0000060 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000100 \0 \0 \v \0 \0 002 003 S Y S T E M D G 0000120 _ 0 0 0 0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000140 \0 \0 \0 \0 \0 \0 \0 \0 S Y S T E M D G 0000160 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000200
[root@ohs1 ~]# dd if=/dev/sdb1 bs=128 count=1|od -c
1+0 records in 1+0 records out 128 bytes (128 B) copied, 2.9095e-05 seconds, 4.4 MB/s 0000000 001 202 001 001 \0 \0 \0 \0 \0 \0 \0 200 310 ; U [ 0000020 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000040 O R C L D I S K A S M D I S K 1 0000060 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000100 \0 \0 \v \0 \0 002 003 S Y S T E M D G 0000120 _ 0 0 0 0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000140 \0 \0 \0 \0 \0 \0 \0 \0 S Y S T E M D G 0000160 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000200
[root@ohs1 ~]#
[root@ohs1 /]# od -N 128 -t c /dev/sdb1 0000000 001 202 001 001 \0 \0 \0 \0 \0 \0 \0 200 310 ; U [ 0000020 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000040 O R C L D I S K A S M D I S K 1 0000060 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000100 \0 \0 \v \0 \0 002 003 S Y S T E M D G 0000120 _ 0 0 0 0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000140 \0 \0 \0 \0 \0 \0 \0 \0 S Y S T E M D G 0000160 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000200 [root@ohs1 /]#
