Important Enable this LUN property only if the connected host does not use failover software. The auto assign property is ignored when the storage system's failover mode for an initiator is set to 1. This property will not interfere with PowerPath's control of a LUN.
Auto assign enables or disables (default) auto assign for a LUN. Auto assign controls the ownership of the LUN when an SP fails in a storage system with two SPs. You enable or disable auto assign for a LUN when you bind it. You can also enable or disable it after the LUN is created without affecting the data on it.
With auto assign enabled, if the SP that owns the LUN fails and the server tries to access that LUN through the second SP, the second SP assumes ownership of the LUN to enable access. The second SP continues to own the LUN until the failed SP is replaced and the storage system is powered up. Then, ownership of the LUN returns to its default owner. If auto assign is disabled in this situation, the second SP does not assume ownership of the LUN, and access to the LUN does not occur.
If you are running failover software on a server connected to the LUNs in a storage system, you must disable auto assignment for all LUNs that you want the software to fail over when an SP fails. In this situation, the failover software, not auto assign, controls ownership of the LUN in a storage system with two SPs.
Note The auto assign property is not available for a Hot Spare LUN.
Roger_Wu
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2014年1月8日 01:00
Auto-trespass和Auo-assign是两个不同的概念。
Auto-trespass指的是failover mode=0。更多解释参考论坛文章：故障转移模式(Failover Mode)简介
Auto-assign的作用直接参考Unisphere帮助手册：
Auto assign for a LUN
Important Enable this LUN property only if the connected host does not use failover software. The auto assign property is ignored when the storage system's failover mode for an initiator is set to 1. This property will not interfere with PowerPath's control of a LUN.
Auto assign enables or disables (default) auto assign for a LUN. Auto assign controls the ownership of the LUN when an SP fails in a storage system with two SPs. You enable or disable auto assign for a LUN when you bind it. You can also enable or disable it after the LUN is created without affecting the data on it.
With auto assign enabled, if the SP that owns the LUN fails and the server tries to access that LUN through the second SP, the second SP assumes ownership of the LUN to enable access. The second SP continues to own the LUN until the failed SP is replaced and the storage system is powered up. Then, ownership of the LUN returns to its default owner. If auto assign is disabled in this situation, the second SP does not assume ownership of the LUN, and access to the LUN does not occur.
If you are running failover software on a server connected to the LUNs in a storage system, you must disable auto assignment for all LUNs that you want the software to fail over when an SP fails. In this situation, the failover software, not auto assign, controls ownership of the LUN in a storage system with two SPs.
Note The auto assign property is not available for a Hot Spare LUN.
o17Uu33DCF12520
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2014年1月8日 23:00
auto assign就是当LUN的原来的owner SP故障的时候，允不允许peer SP接管这个LUN成为新的owner。
ALUA就是当LUN不能通过原来的owner SP访问的时候，（例如：owner SP故障或者主机到LUN的path故障），peer SP接收到IO请求的时候，他会采取怎样的行动，例如：
当path故障了，peer SP不切换ownership只把IO请求转发给owner SP处理；
当owner SP故障了且LUN上的auto assign启用了，peer SP就直接接管这个LUN成为新的owner。
andyhsu
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2014年1月8日 23:00
請問Auto assign 的功用是否與Failover Mode 4 (Active/Active (ALUA) Failover 模式)相同？
o17Uu33DCF12520
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2014年1月9日 00:00
那么LUN不可存取
andyhsu
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2014年1月9日 00:00
kevin 請教一下，若ALUA當owner SP故障，auto assign disable，LUN會直接變為不可存取嗎？還是一樣把IO轉發？？