“Migratable” means the drives can be moved from an existing Synology system and used for migration. The knowledge base says Synology differentiates this from unsupported cases such as drives moved to an older OS version, which would show Not supported by the current OS version. It also notes that for Migration Assistant, data, packages, and system configurations can be migrated, but some items are not migrated.
Safe next steps from the knowledge base:
- Make sure the destination device supports the migration scenario.
- If you use Migration Assistant, install it on the destination device.
- For Migration Assistant, the source device requires DSM 6.0 or above, and the destination device requires DSM 7.0 or above.
- The destination NAS must have the same or newer DSM version than the source device.
- Be aware that Migration Assistant migrates data, packages, and system configurations, but does not migrate items such as:
- Synology Account settings
- Licenses
- Network settings in Control Panel, including:
- Server name, Default gateway, IPv6 default gateway in General tab
- Network Interface, except for VPN profile, IPv6 Tunneling, MTU value in IPv4 settings, and 802.1X
- Static Route
- Also note that Migration Assistant does not support Peta Volume migration.
If you are migrating a high-availability cluster, the guide says to do a Switchover from Synology High Availability > Cluster > Manage > Switchover, migrate the passive side, and then Switchover again to make the destination NAS the new active server.
If you want, I can also summarize the differences between Migration Assistant, HDD migration, and Hyper Backup using only the provided knowledge base.
Sources used: [8], [9], [11], [13], [1]