What Happens to My Fivetran Syncs When I Patch My SSH Server?

Question

What happens if my SSH server reboots during a sync? What precautions should I take before patching to prevent disruption to my Fivetran syncs?

Environment

• Database connectors
• Connection method: SSH tunnel on Linux servers

Answer

If the SSH server reboots during a sync, the SSH tunnel drops and the in-progress sync fails because Fivetran loses connectivity. Fivetran automatically retries the sync. After the SSH server is back online, the connection resumes from its stored state or cursors. No manual action is required.

Before patching, take the following precautions:

• Pause your connections during the maintenance window to avoid repeated failures and alerts. To pause a connection, go to the connection overview page in Fivetran and set the Enabled toggle to OFF. After maintenance, set the toggle back to ON.
• Ensure the SSH server comes back online with the same SSH host key. If the host key changes, you must re-validate the SSH host fingerprint in Fivetran. For more information, see Validated Certificates & Keys.
• Verify that the bastion hostname or IP address and port remain the same. If they change, update them in Fivetran. Ensure that network access rules still allow Fivetran to reach the bastion's SSH port.