有人说修改domain id时，hpux和aix需要重新认盘。

正是听到有这种说法，于是前段时间不敢贸然地去修domain id。

回来仔细看了一下文档，发现：

The PID is a 24-bit address built from three 8-bit fields:
• domain
• area_ID
• AL_PA

There are several routine maintenance procedures which might result in a device receiving a new PID.
Examples include, but are not limited to:
• Changing compatibility mode settings
• Changing switch domain IDs
• Merging fabrics
• Relocating devices to new ports or new switches (that is, for Add, Move, Change type operations)
• Updating the core PID format
• Using hot spare switch ports to deal with failures

• unplugging the device from one port and plugging it into a different port as part of fabric maintenance

Some device drivers use the PID to map logical disk drives to physical Fibre Channel counterparts.
Most drivers can either change PID mappings dynamically (called dynamic PID binding) or use the
WWN of the Fibre Channel disk for mapping (called WWN binding).

Some older device drivers behave as if a PID uniquely identifies a device (they use static PID binding).
These device drivers should be updated, if possible, to use WWN or dynamic PID binding instead,because static PID binding creates problems in many routine maintenance scenarios.
Fortunately, very few device drivers still behave this way.
Many current device drivers enable you to select static PID
binding as well as WWN binding. You should only select static binding if there is a compelling reason,and only after you have evaluated the impact of doing so.

也就是说如果原先主机上面的盘是通过wwn绑定或动态pid绑定的话， 应该是不需要认盘的。而如果是静态的pid绑定的话是需要认盘的。

一般情况下，都是采用wwn绑定的，所以我觉的很有可能是不需要重新认盘的。

下次改domain id时我们做个测试，看看是不是真的需要重新认盘的。