Here, we report both ac and dc magnetization, thermodynamic and electric properties of hexagonal Ba$_3$NiIr$_2$O$_9$. The Ni$^{2+}$ (spin-1) forms layered triangular-lattice and interacts antiferromagnetically while Ir$^{5+}$ is believed to act as magnetic link between the layers. This complex magnetic interaction results in magnetic frustration leading to a spin-glass transition at $T_f$ $sim$ 8.5 K. The observed magnetic relaxation and aging effect also confirms the nonequilibrium ground state. The system further shows large exchange bias which is tunable with cooling field. Below the Curie-Weiss temperature $theta_{CW}$ ($sim$ -29 K), the magnetic specific heat $C_m$ displays a broad hump and at low temperature follows $C_m = gamma T^alpha$ dependence where both $gamma$ and $alpha$ show dependence on temperature and magnetic field. A sign change in magnetoresistace is observed which is due to an interplay among magnetic moment, field and spin-orbit coupling.
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