LUNZ详解
LUNZ在日常运维中经常简单，也碰到少客户有碰到类似的问题，不知道如何处理。
LUNZ，是在主机和存储之间还没有建立连接的时候，建立沟通桥梁的工具。（个人认为这句话已经是高度提炼过了）当存储有一个LUN 0 的设备MAP给主机的时候，LUNZ就可以功成身退了。
另外，如果客户没有使用LUN0的设备，则需要disable arraycommpath。当然，disable这个参数是有代价的，还需要考虑failovermode and powerpath configuration. So, i need do more research about "arraycommpath" parametic.
The following is come from EMC official knowledge:
LUNZ has been implemented on CLARiiON arrays to make arrays visible to the host OS and PowerPath when no LUNs are bound on that array. When using a direct connect configuration and there is no Navisphere Management station to talk directly to the array over IP, the LUNZ can be used as a pathway for Navisphere CLI to send bind commands to the array. LUNZ also makes arrays visible to the host OS and PowerPath when the host's initiators have not yet `logged in' to the Storage Group created for the host. Without LUNZ, there would be no device on the host for Navisphere Agent to push the initiator record through to the array. This is mandatory for the host to log in to the Storage Group. Once this initiator push is done, the host will be displayed as an available host to add to the Storage Group in Navisphere Manager (Navisphere Express).
In summary, this occurs because the arraycommpath setting of 1 creates a virtual LUN 0 for communication with the storage system.
A way of getting rid of LUNZ is to set arraycommpath to a value of 0. The arraycommpath option enables or disables a communication path from the server to the storage system.
This does not work on AX-series arrays. AX150 arrays are shipped with the failover/arraycommpath mode configured as 1 by default. It is not possible to change the failover mode using Navisphere Express or Navisphere Manager. Also, it is not possible to configure the failover mode and arraycommpath setting using CLI.
For CLARiiON AX-series you would need to use storagegroup command:
storagegroup sethost -arraycommpath
Caution! Do not issue the storagegroup command unless you know the appropriate value for the type of failover software running on the attached servers. The command is designed for transition from one type of failover software to another. Changing the arraycommpath mode to the wrong value will make the storage system inaccessible.