MPIO Driver Migration Without Application Downtime
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Solution Overview
Problem
Existing storage systems require significant application downtime for updating or replacing multi-path input-output (MPIO) drivers, disrupting IO operations and causing substantial downtime.
Innovation Solution
The technique involves migrating control of multi-path logical devices from a current MPIO driver to a target MPIO driver by mapping IO entry points, allowing seamless transition without significant downtime, where the target driver takes over control of existing multi-path logical devices created by the current driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the current MPIO driver is updated or replaced with a new version or different driver, then the driver functionality is improved or updated, but significant application downtime and outages occur
Solution Approach 1:
The target MPIO driver is installed and configured in advance before the current driver is removed. The migration process transfers control of multi-path logical devices from the current driver to the target driver while the current driver is still operational, allowing the transition to be prepared beforehand without interrupting IO operations
Solution Approach 2:
The migration process acts as an intermediary mechanism that transfers control of multi-path logical devices from the current MPIO driver to the target MPIO driver. This intermediary process allows the transition between drivers to occur without requiring application downtime, as the transfer of control is handled separately from the application's IO operations
2Adaptability or versatility
If the current MPIO driver is replaced with a new driver, then new functionality and improvements are achieved, but IO operations are disrupted and reconfiguration is required
Solution Approach 1:
The migration process maintains continuous IO operations throughout the driver transition. The target MPIO driver assumes control of the multi-path logical devices without interrupting the IO operations, ensuring that the useful action of data transfer continues uninterrupted while the driver control is transferred
3Adaptability or versatility
If multi-path logical devices are recreated with a new MPIO driver, then the new driver can control them, but significant downtime and reconfiguration are required
Solution Approach 1:
The target MPIO driver copies or transfers the control of existing multi-path logical devices from the current driver rather than recreating them. This copying process preserves the existing device configurations and associations, allowing the new driver to control the same logical devices without requiring reconfiguration or recreation
Data Source
AI summary
An apparatus in one embodiment comprises a host device that includes a set of input-output (IO) queues and a current multi-path input-output (MPIO) driver configured to select IO operations from the set of IO queues for delivery to the storage system. The current MPIO driver is configured to group a plurality of paths from the host device to a logical unit number of the storage system into a multi-path logical device. The host device is configured to install a target MPIO driver and to migrate control of the multi-path logical device to the target MPIO driver from the current MPIO driver where the migration comprises transferring IO entry points of the multi-path logical device from the current MPIO driver to the target MPIO driver. The host device is configured to deliver IO operations selected by the target MPIO driver to the storage system using the multi-path logical device.