Failover Boot via LUID and WWN Mapping
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Solution Overview
Problem
In storage networks, failover operations often result in standby servers being unable to access logical units (LUs) due to changes in World Wide Names (WWNs) of storage ports, leading to failed boot operations when switching from an active to a standby server, as existing technologies do not effectively manage access control lists across multiple storage ports.
Innovation Solution
An integrated platform with active and standby servers and a storage device, where each storage port is assigned a unique WWN and logical volume is assigned a Logical Unit ID (LUID), with boot search information copied from the active server to the standby server during failover, ensuring seamless access to logical volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a storage device directly couples multiple servers without using an FC switch, then the cost of the storage network is reduced, but the standby server cannot access the LU after failover due to WWN changes
Solution Approach 1:
The invention segments the access control mechanism by introducing a new abstraction layer (LUID) that separates the logical volume identification from the physical storage port WWN. This allows the standby server to access the LU through a different storage port WWN while maintaining the same logical volume identity, thus enabling failover without requiring FC switches.
Solution Approach 2:
The invention changes the parameter used for LU identification from WWN (physical port identifier) to LUID (logical volume identifier). This parameter change allows the system to maintain LU accessibility across different storage ports during failover, solving the problem where WWN changes prevent LU access after server switching.
2Ease of operation
If access control lists are applied in units of storage ports, then access control is simplified, but the same LU cannot be accessed by different servers through different storage ports
Solution Approach 1:
The invention makes the LUID a universal identifier that can be accessed through multiple different storage port WWNs. The LUID serves multiple functions: it identifies the logical volume, enables access control, and maintains consistency across different physical connections, allowing the same LU to be accessed by multiple servers through different storage ports.
Solution Approach 2:
The LUID acts as an intermediary between the physical storage ports and the logical volumes. Instead of directly binding access control lists to WWNs, the system uses LUID as a mediator that connects multiple WWNs to a single LU, enabling flexible multi-server access while maintaining simplified access control management.
Data Source
AI summary
Provided is an integrated platform that has an active server, a standby server and a storage device. The storage device has a plurality of storage ports, and a WWN is assigned to each of the plurality of storage ports. An LUID is assigned to each of a plurality of logical volumes provided by the storage device. The active and standby servers are connected, respectively, to storage ports in a one-to-one relationship. The active server has boot search information that associates the WWN of a storage port at a connection destination; the LUN of a boot logical volume, which is a logical volume accessed during booting; and the LUID of the boot logical volume with one another. When a failover is executed, the boot search information of the active server is copied to the standby server.