@@Harsha_vardhan1 Hi Harsha it's not wrong if we can say AG is server level but the thing is we can't replicate server level logins and jobs etc., so in my openion AG is not a server level even though we can add all the databases to AG.
No, It is a database level, because we can't share the resources(eg. drive) between servers or nodes. its an mix of mirroring(fast data synchronization& automatic failover without witness server),and Log shipping (one to many relation, and secondary is readable).Only clustering is server level! and always on only need window clustering for the availability group to be created as a role so we can do a manual failover , but we don't need SQL clustering for always on! we install standalone sql instance on the primary replica, and we add a the sql instance on the existing node on the secondary replica. I hope it will help
