You must use the 12V, 0.5 amp power supply that came with your NETGEAR GS308v2 switch.
Do not use any power supplies with your GS308v2 switch other than the power supply that came with your switch. Using a different power supply will damage your switch and could cause a safety hazard. This will also void your warranty.
NETGEAR is aware of an error in the documentation that shipped with some GS308v2 units. Some GS308v2 Installation Guides incorrectly state that the included power supply provides 1.0 amp. However, the included power supply actually provides 0.5 amps.