+- snapshot
+
+<zpool> ::= <vdev> <log> <cache> <spare> | <vdev> <log> <cache> <spare> <zpool>;
+<vdev> ::= <diskset> | <mirror> | <raidz1> | <raidz2> | <raidz3>;
+<mirror> ::= "disk" "disk" | "disk" <mirror>;
+<raidz1> ::= "disk" "disk" "disk" | "disk" <raidz1>;
+<raidz2> ::= "disk" "disk" "disk" "disk" | "disk" <raidz2>;
+<raidz3> ::= "disk" "disk" "disk" "disk" "disk" | "disk" <raidz3>;
+<log> ::= "internal" | <diskset> | <mirror>;
+<cache> ::= "internal" | <diskset>;
+<spare> ::= "" | <diskset>;
+<diskset> ::= "disk" | "disk" <diskset>;