格式化分区，报/dev/sdb1 is apparently in use by the system; will not make a filesystem here!

[root@RAC2 ~]# mke2fs /dev/sdb1
mke2fs 1.39 (29-May-2006)
/dev/sdb1 is apparently in use by the system; will not make a filesystem here!
[root@RAC2 ~]# 
[root@RAC2 ~]# dmsetup status
vbirdvg-vbirdlv2: 0 204800 linear 
vbirdvg-vbirdlv1: 0 204800 linear 
vbirdvg-vbirdlv1: 204800 2097152 linear 

刚测试的有一个vg，将该vg删除。
[root@RAC2 ~]# vgremove vbirdvg
或者
[root@localhost ~]# dmsetup remove_all
[root@localhost ~]# dmsetup status
No devices found

dmsetup，这个命令帮助我们“组装”、“解散”、“监视”我们自己的虚拟存储结构。

SYNOPSIS
       dmsetup help [-c|-C|--columns]
       dmsetup create device_name [-u uuid] [--notable | --table <table> | table_file]
       dmsetup remove [-f|--force] device_name
       dmsetup remove_all [-f|--force]
       dmsetup suspend [--nolockfs] [--noflush] device_name
       dmsetup resume device_name
       dmsetup load device_name [--table <table> | table_file]
       dmsetup clear device_name
       dmsetup reload device_name [--table <table> | table_file]
       dmsetup rename device_name new_name
       dmsetup message device_name sector message
       dmsetup ls [--target target_type] [--exec command] [--tree [-o options]]
       dmsetup info [device_name]
       dmsetup info -c|-C|--columns [--noheadings] [--separator separator] [-o fields] [-O|--sort sort_fields] [device_name]
       dmsetup deps [device_name]
       dmsetup status [--target target_type] [device_name]
       dmsetup table [--target target_type] [device_name]
       dmsetup wait device_name [event_nr]
       dmsetup mknodes [device_name]
       dmsetup udevflags cookie
       dmsetup udevcomplete cookie
       dmsetup udevcomplete_all
       dmsetup udevcookies
       dmsetup targets
       dmsetup version
       dmsetup setgeometry device_name cyl head sect start
       dmsetup splitname device_name [subsystem]

       devmap_name major minor
       devmap_name major:minor