ZPOOL_CONFIG_IS_SPARE
ASSERT_EQ(0, nvlist_add_uint64(m_vdevConfig, ZPOOL_CONFIG_IS_SPARE, 1));
(void)nvlist_lookup_uint64(m_config, ZPOOL_CONFIG_IS_SPARE, &is_spare);
if (nvlist_lookup_uint64(m_config, ZPOOL_CONFIG_IS_SPARE, &spare) != 0)