To ensure continuous access, Xsan supports standby MDCs . If the primary controller fails, a standby takes over within seconds, keeping the filesystem online for all clients. Xsan Management Guide - Apple Developer
is Apple’s implementation of the SAN (Storage Area Network) file system, based on the Quantum StorNext File System. It enables multiple macOS workstations and servers to simultaneously access shared block-level storage with high performance. Unlike traditional file servers (NAS), which operate over a network protocol, Xsan provides direct block-level access to a shared storage pool, appearing to the user as a local volume while managing concurrency across the network. xsan filesystem access
If cvadmin shows "disconnected": Restart the cvfs service: sudo systemsetup -setremotelogin off/on (or sudo launchctl unload/load ). To ensure continuous access, Xsan supports standby MDCs