HPUX 11.31 V3版本的一个最大的变化就是磁盘设备名（device special file－DSF)
的变化，采用简洁的称为永久设备名（Persistent device special files)，尽管为了兼容性，还保留了传统的硬件路径式的命名方式（即cXtYdZ）。
V3以前的版本采用的是legacy DSF，这种名字是和硬件路径绑定的，如/dev/dsk/c3t15d0，是Instance 3， SCSI ID 15，LUN 0。如果采用这种命名方式，对应每一条物理路径就会有一个设备名，对于XP磁盘阵列上的一个lun或者EVA上的Vdisk就可能有8条路径之多（对于V2系统一个LUN最多支持8个路径，V3可以32个），并且如果San环境变化，如换HBA卡，改变Switch Domain ID等还会引起设备名的改变。由于多路径，考虑IO问题，于是有了Secure Path或者Auto Path这样的软件。
V3采用永久设备名后，这些问题变得简单了，如/dev/disk/disk3，对于一个lun只有一个设备名，并且不再和物理路径绑定，而是和LUN的 WorldWide Identifier (WWID)绑定，只要WWID不变，设备名就不变，把物理设备拔掉再插回也不变，新加入的设备只会分配新的设备名。不再需要多路径软件了，能自动实现load balance功能，如果链路失败系统会取消该链路，当发现新链路时自动发现并加入load balance。下面介绍针对永久设备名的出现几个命令的使用。
一， ioscan的用法
# ioscan -N –fknCdisk 显示永久设备名
Class I H/W Path Driver S/W State H/W Type Description
===================================================================
disk 2 64000/0xfa00/0x0 esdisk CLAIMED DEVICE TEAC DV-28E-
C
/dev/disk/disk2 /dev/rdisk/disk2
disk 3 64000/0xfa00/0x1 esdisk CLAIMED DEVICE HP 36.4GST33675
3LC
/dev/disk/disk3 /dev/rdisk/disk3
/dev/disk/disk3_p1 /dev/rdisk/disk3_p1
/dev/disk/disk3_p2 /dev/rdisk/disk3_p2
/dev/disk/disk3_p3 /dev/rdisk/disk3_p3
disk 5 64000/0xfa00/0x5 esdisk CLAIMED DEVICE HP 36.4GST33675
3LC
/dev/disk/disk5 /dev/rdisk/disk5
# ioscan -m lun 显示永久设备名
Class I Lun H/W Path Driver S/W State H/W Type Health Description
======================================================================
disk 2 64000/0xfa00/0x0 esdisk CLAIMED DEVICE online TEAC
DV-28E-C
0/0/2/0.0.0x0.0x0
/dev/disk/disk2 /dev/rdisk/disk2
disk 3 64000/0xfa00/0x1 esdisk CLAIMED DEVICE online HP 36.4
GST336753LC
0/1/1/0.0x1.0x0
/dev/disk/disk3 /dev/rdisk/disk3
/dev/disk/disk3_p1 /dev/rdisk/disk3_p1
/dev/disk/disk3_p2 /dev/rdisk/disk3_p2
/dev/disk/disk3_p3 /dev/rdisk/disk3_p3
disk 5 64000/0xfa00/0x5 esdisk CLAIMED DEVICE online HP 36.4
GST336753LC
0/1/1/1.0x2.0x0
/dev/disk/disk5 /dev/rdisk/disk5
/dev/disk/disk5_p1 /dev/rdisk/disk5_p1
/dev/disk/disk5_p2 /dev/rdisk/disk5_p2
/dev/disk/disk5_p3 /dev/rdisk/disk5_p3
# ioscan -m dsf 查看永久设备名和旧设备名之间的对应关系
Persistent DSF Legacy DSF(s)
========================================
/dev/rdisk/disk2 /dev/rdsk/c0t0d0
/dev/rdisk/disk3 /dev/rdsk/c2t1d0
/dev/rdisk/disk3_p1 /dev/rdsk/c2t1d0s1
/dev/rdisk/disk3_p2 /dev/rdsk/c2t1d0s2
/dev/rdisk/disk3_p3 /dev/rdsk/c2t1d0s3
/dev/rdisk/disk5 /dev/rdsk/c3t2d0
# ioscan -P health -C disk 检查磁盘online状态
Class I H/W Path health
===============================
disk 2 64000/0xfa00/0x0 online
disk 3 64000/0xfa00/0x1 online
disk 5 64000/0xfa00/0x5 online
# rmsf –L 取消旧设备命
WARNING: This command may be disruptive to the system.
Before running this command, make sure you have first run
iofind(1M) and migrated all applications using legacy device
special files. Please refer to the man page of rmsf(1M) to
verify the possible side effects of the option '-L'.
Do you want to continue ?
(You must respond with 'y' or 'n'.): y
rmsf: Legacy mode has been successfully disabled
# ioscan -funCdisk
# insf –L 恢复旧设备名
This command will re-install all legacy I/O nodes and legacy DSFs.
Do you want to continue ?
(You must respond with 'y' or 'n'.): y
insf: Legacy mode has been successfully enabled
# ioscan -funCdisk
Class I H/W Path Driver S/W State H/W Type Description
=======================================================================
disk 1 0/0/2/0.0.0.0 sdisk CLAIMED DEVICE TEAC DV-28E-C
/dev/dsk/c0t0d0 /dev/rdsk/c0t0d0
disk 0 0/1/1/0.1.0 sdisk CLAIMED DEVICE HP 36.4GST336753LC
/dev/dsk/c2t1d0 /dev/rdsk/c2t1d0
/dev/dsk/c2t1d0s1 /dev/rdsk/c2t1d0s1
/dev/dsk/c2t1d0s2 /dev/rdsk/c2t1d0s2
/dev/dsk/c2t1d0s3 /dev/rdsk/c2t1d0s3
disk 4 0/1/1/1.2.0 sdisk CLAIMED DEVICE HP 36.4GST336753LC
/dev/dsk/c3t2d0 /dev/rdsk/c3t2d0
如果采用永久设备名，在做vgimport时，需要使用新参数N，否则将使用旧设备文件名。
# vgimport -s -m /tmp/vgdata.map -N vgdata
vgimport: Volume group "/dev/vgdata" has been successfully created.
Warning: A backup of this volume group may not exist on this machine.
Please remember to take a backup using the vgcfgbackup command after activating
the volume group.
# strings /etc/lvmtab
/dev/vg00
/dev/disk/disk3_p2
/dev/vgdata
/dev/disk/disk5
# vgimport -s -m /tmp/vgdata.map vgdata
vgimport: Volume group "/dev/vgdata" has been successfully created.
Warning: A backup of this volume group may not exist on this machine.
Please remember to take a backup using the vgcfgbackup command after activating
the volume group.
# strings /etc/lvmtab
/dev/vg00
/dev/disk/disk3_p2
/dev/vgdata
/dev/dsk/c3t2d0
改变设备名，如将disk5――>disk4,先删除原来的设备名，再生成新的设备名。
# rmsf /dev/disk/disk5 /dev/rdisk/disk5
# ioscan -m lun
Class I Lun H/W Path Driver S/W State H/W Type Health Description
======================================================================
disk 2 64000/0xfa00/0x0 esdisk CLAIMED DEVICE online TEAC
DV-28E-C
0/0/2/0.0.0x0.0x0
/dev/disk/disk2 /dev/rdisk/disk2
disk 3 64000/0xfa00/0x1 esdisk CLAIMED DEVICE online HP 36.4
GST336753LC
0/1/1/0.0x1.0x0
/dev/disk/disk3 /dev/rdisk/disk3
/dev/disk/disk3_p1 /dev/rdisk/disk3_p1
/dev/disk/disk3_p2 /dev/rdisk/disk3_p2
/dev/disk/disk3_p3 /dev/rdisk/disk3_p3
disk 5 64000/0xfa00/0x5 esdisk CLAIMED DEVICE online HP 36.4
GST336753LC
0/1/1/1.0x2.0x0
# mksf -C disk -I 5 /dev/disk/disk4
# mksf -C disk -I 5 -r /dev/rdisk/disk4
# ioscan -m lun
Class I Lun H/W Path Driver S/W State H/W Type Health Description
======================================================================
disk 2 64000/0xfa00/0x0 esdisk CLAIMED DEVICE online TEAC
DV-28E-C
0/0/2/0.0.0x0.0x0
/dev/disk/disk2 /dev/rdisk/disk2
disk 3 64000/0xfa00/0x1 esdisk CLAIMED DEVICE online HP 36.4
GST336753LC
0/1/1/0.0x1.0x0
/dev/disk/disk3 /dev/rdisk/disk3
/dev/disk/disk3_p1 /dev/rdisk/disk3_p1
/dev/disk/disk3_p2 /dev/rdisk/disk3_p2
/dev/disk/disk3_p3 /dev/rdisk/disk3_p3
disk 5 64000/0xfa00/0x5 esdisk CLAIMED DEVICE online HP 36.4
GST336753LC
0/1/1/1.0x2.0x0
/dev/disk/disk4 /dev/rdisk/disk4
如果更换硬盘，还想使用原来的设备名，可以使用io_redirect_dsf命令。因为换上的新硬盘，系统会分配一个新的设备名。
# io_redirect_dsf –d /dev/disk/disk3 –n /dev/disk/disk1
