The Vess R3000 Series offers three Sync Modes when creating new NAS Shares and Volumes in Advanced Pool. Each mode determines how synchronous transactions are handled.
1. Standard: In this mode, synchronous share transactions—such as `fsync`, `O_DSYNC`, `O_SYNC`, and others—are written to the intent log.
2. Always: Ensures every share transaction is written and flushed to stable storage before the system call returns. This setting prioritizes data stability but can significantly impact performance. Always is the default sync mode.
3. Disabled: Disables synchronous requests. Share transactions are only committed to stable storage during the next transaction group commit, which may take several seconds. While this mode provides the best performance, it also poses risks.
Caution: Using the Disabled mode can be risky, as it ignores applications’ synchronous transaction requirements (e.g., for databases or NFS operations). Setting this mode on an active root or shared volume may result in unexpected behavior, data loss, or increased vulnerability to replay attacks. Use Disabled only if you fully understand these risks.
To select a sync mode, go to the “Expand Advanced Settings” option in the Web Interface.
