Kernel-based crash-consistency coordinator

The present invention relates to computer disk storage. More specifically, the invention relates to the creation and maintenance of logical volumes used in system crash recovery and the like. A snapshot system capable of capturing snapshots of multiple volumes wherein the snapshots are coordinated. A snapshot manager determines which volumes are to be involved in a snapshot operation, and issues a message to the file system for each volume involved, each message including information sufficient to identify the volumes involved in the snapshot operation. Each file system passes its respective message down to a coordinator mechanism. The coordinator mechanism coordinates the state of each of the volumes, such as by holding writes thereto, to put each volume into a quiescent state, and then enables the snapshot to be captured. When the snapshots are captured, a snapshot set will include snapshots that are coordinated across the multiple volumes. The coordinator mechanism releases any writes being held for the volumes involved.