Long story short, each M4300 switch has a "native" SDM with its maximum capacities (table size, constants, etc.). You can use it in standalone mode, or when you are building a stack with same models (same table size). But when you have mixed stacks, the table sizes won't be the same, hence the generic SDM templete which is the "minimum common denominator" allowing for mixed stacks.
You can read the table sizes for each M4300 models on page 5, see "Performance at a glance":
A stack requires an uniform table size across all stack members.
SDM (System Data Management, or switch database) templates allow for granular system resources distribution depending on IPv4 or IPv6 applications: • ARP Entries (the maximum number of entries in the IPv4 Address Resolution Protocol ARP cache for routing interfaces) • IPv4 Unicast Routes (the maximum number of IPv4 unicast forwarding table entries) • IPv6 NDP Entries (the maximum number of IPv6 Neighbor Discovery Protocol NDP cache entries) • IPv6 Unicast Routes (the maximum number of IPv6 unicast forwarding table entries) • ECMP Next Hops (the maximum number of next hops that can be installed in the IPv4 and IPv6 unicast forwarding tables) • IPv4 Multicast Routes (the maximum number of IPv4 multicast forwarding table entries) • IPv6 Multicast Routes (the maximum number of IPv6 multicast forwarding table entries)
You will find SDM templates information in Tech Spec section of the datasheet later on, you can just Ctrl-F and search for SDM.
