- Real-time data replication between the active and passive servers to maintain data consistency and maximize service availability
- Automatic failover to minimize system interruption resulting from service failures or hardware unavailability
- Unified and friendly user interface to easily manage and monitor the high-availability cluster
- Easy-to-navigate dashboard to closely monitor CPU, memory, and drive utilization on both servers
- Intuitive and easy-to-follow troubleshooting process
Synology High Availability
Features
Specifications
- Automatic failover ensures system availability upon:
- Service unavailability:
- CIFS
- iSCSI
- AFP
- FTP
- NFS
- Synology Directory Server
- Web Services
- Crashed storage space
- Cluster network disconnection (The network between the high-availability cluster and the clients)
- System unavailability on the active server
- Service unavailability:
- Automatic failover and manual switchover complete within minutes to achieve minimal downtime (See limitation 8)
- Identical memory size on both active and passive servers is not required but highly suggested for consistent performance (See limitation 9)
- High-availability cluster can be created with two compatible Synology NAS (Learn More)
- Easy-to-navigate dashboard to closely monitor the CPU, memory, and drive utilization of both host servers
- Real-time data replication between the active and passive servers to maintain data consistency
- Supports Quorum Server to effectively minimize the occurrence of split-brain error
- Compatible with intensive workloads and various virtualization solutions, e.g., VMware®, vSphere™, Microsoft® Hyper-V®, Citrix® XenServer™, and OpenStack Cinder
- Package not supported in a high-availability cluster: PetaSpace
- Maximum total number of volumes and LUNs per high-availability cluster: 64
- Maximum total capacity of volumes and LUNs per high-availability cluster: 400 TB
- Functions not available in a high-availability cluster:
- Scheduled power-on
- HDD hibernation
- DHCP server
- IPv6
Limitations
- USB external devices are only accessible when connected to the active server
- Link Aggregation cannot be modified after the high-availability cluster is created
- Heartbeat connection is strongly recommended to be a direct connection between the active and the passive servers (There is no guarantee the connection will be stable or reliable if the Heartbeat connection passes through a network switch)
- Drive position within the active and the passive servers cannot be changed after the high-availability cluster is created
- Direct system migration is not supported in a high-availability cluster (Cluster migration requires upgrading the passive and active servers in order)
- Passive server is not available for user login as all operations are processed on the active server
- System resources will be partially allocated to create and maintain a high-availability cluster, resulting in a potential 15% impact on overall system performance
- Duration of automatic failover and switchover may vary depending on product model, system utilization, volume size, number of packages running on the high-availability cluster, and other factors
- Failover will not be available if SSD cache is created on servers that do not have identical memory size and are in a high-availability cluster