Boot Volume Synchronization via Storage Controller for SAN Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for recovering and booting a computer system using a Storage Area Network (SAN) are challenging due to the inability to maintain an up-to-date snapshot of the boot volume, especially during initial boot processes, and the lack of multipathing capabilities during these processes, which hinders access to replicated boot volumes on remote SANs.
Innovation Solution
A method that synchronizes the boot volume between a local storage device and a SAN by writing data to both simultaneously, allowing the computer system to boot from the SAN, and utilizing a storage controller and network adapter to manage data replication and journaling for continuous synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the boot volume is replicated to a remote SAN for disaster recovery, then the system can recover from local failures, but the snapshot cannot be kept up-to-date because the boot volume is actively controlled by the operating system and constantly updated
Solution Approach 1:
The system separates the boot volume management into two independent paths: local active boot volume for system operations and remote replicated boot volume for disaster recovery. The storage controller independently manages write operations to both locations without requiring system intervention, resolving the conflict between active system control and snapshot synchronization.
Solution Approach 2:
The storage controller acts as an intermediary between the system and the boot volume, interceptating write requests and simultaneously updating both the local boot volume and the remote SAN copy. This intermediary mechanism ensures synchronization without requiring the system to be aware of or involved in the replication process.
2Ease of operation
If the host bus adapter is configured to boot from the local SAN logical unit, then the system can boot locally, but it cannot access the replicated boot volume on the remote SAN during initial boot process due to lack of multipath driver
Solution Approach 1:
The storage controller provides universal access to the boot volume by presenting the same logical unit identifier through multiple paths (local and remote). The system is configured to boot from a single logical unit identifier, but the storage controller transparently redirects to the appropriate physical location (local or remote SAN), providing both simplicity and flexibility.
Solution Approach 2:
The storage controller automatically determines the availability of local and remote paths and self-manages the boot process by redirecting the system to the appropriate boot volume location without requiring multipath drivers or complex system configuration. The controller services the boot request itself based on path availability.
3Manufacturing precision
If the local SAN forwards write requests to the remote SAN, then the snapshot can be kept up-to-date, but the system cannot handle events where the configured path is not active and the logical unit is managed by a secondary controller
Solution Approach 1:
The storage controller proactively monitors the active path status and preemptively switches to the remote SAN path when local path unavailability is detected, before the system attempts to boot. This preliminary action ensures the boot volume is accessible from the remote SAN before the boot process begins, handling path failures reliably.
Solution Approach 2:
The storage controller continuously monitors path availability and uses this feedback to dynamically adjust the boot source. When the local path is unavailable or managed by a secondary controller, the controller receives feedback about the path status and automatically redirects boot operations to the remote SAN, ensuring continuous availability.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Methods and systems for recovering and booting a computer system using a SAN. The computer system comprises a local storage device. A request for writing data to a boot volume on the local storage device is received. The data is written to the local storage device, as well as to the SAN at substantially the same time as receiving the request. The computer system can then be booted using the data written to the SAN.