User`s guide

Synology DiskStation User's Guide
Based on DSM 4.2
86 Chapter 17: Provide Nonstop Service with Synology High Availability
Install Synology High Availability
Synology High Availability can be installed by going to Main Menu > Package Center.
System Requirements
Implementation of Synology High Availability requires two identical Synology servers to act as active and passive
servers
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System Requires
. Before the two servers are combined into a high-availability cluster, the Synology High Availability
Wizard will check for the following hardware and software limitations to ensure that a high-availability cluster can
be created.
 Synology Server: Both the active and passives servers must be identical models and support Synology High
Availability.
 DSM Version: The same version of DSM must be installed on both the active and passive servers.
 Package Version: The same version of Synology High Availability must be installed on both Synology servers.
Volume and Hard Disk
Please note the following guidelines regarding Disk Group, volume, and hard disk management.
 Storage Volume: In order to accommodate data replication, the storage capacity of the passive server must
be equal to or larger than the capacity of the active server. It is strongly advised that the storage capacity of
both servers be completely identical to reduce the chances of inconsistencies.
 Number of Disks: Both the active and passive servers must have the same quantity of hard disks. In addition,
hard disk numbering and position must correspond in both servers.
 SHR Format Unsupported: SHR format volumes are not supported. Please ensure that the Synology server
which will act as the active server does not contain SHR volumes.
Network Environment
Please note the following guidelines regarding network settings.
 Network Settings: Both servers of the high-availability cluster must be assigned static IP addresses. Please
ensure that your Synology servers are both configured with static rather than DHCP IP addresses. In addition,
ensure that the IP addresses of both servers are accessible and belong to the same subnet; otherwise errors
might occur when initiating a switchover to the passive server.
 Number of LAN Ports: Both servers must have the same number of LAN ports. If your Synology NAS is
equipped with additional network card interfaces, these network cards also count as additional LAN ports.
 PPPoE Unsupported: Synology High Availability does not support PPPoE. Please ensure that PPPoE is
switched off before creating a high-availability cluster.
 Link Aggregation Unsupported: Synology High Availability does not support link aggregation. Please ensure
that link aggregation is switched off before creating a high-availability cluster.
 Wi-Fi Unsupported: Synology High Availability does not support Wi-Fi. Please ensure that Wi-Fi is switched
off before creating a high-availability cluster.
 VLAN Unsupported: Synology High Availability does not support VLAN. Please ensure that VLAN is switched
off before creating a high-availability cluster.
Storage Manager Limitations
Once a high-availability cluster has been created, certain options in Storage Manager will be unavailable.
Available Options: The following options are still available when a high-availability cluster exists:
 Expand Disk Groups or volumes by adding or replacing hard disks (only for multiple volumes or iSCSI LUNs
on RAID).
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Synology High Availability can only be installed on certain models.