I didn't quite understand the question:
"should i configure standby tunnel, need to configure another vpn gateway on-premises"
Every Azure VPN gateway consists of two instances in an active-standby configuration. For any planned maintenance or unplanned disruption that happens to the active instance, the standby instance would take over (failover) automatically, and resume the S2S VPN or VNet-to-VNet connections
Active-active gateways have two Gateway IP configurations and two public IP addresses and there is no additional cost to use active-active
if you need Dual-redundancy you should provision 4 tunnels, 2 each side, and use BGP
Get in touch if you need more help with this issue.
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