数据库服务器做了镜像之后，发现有错误信息

The server instance Witness rejected configure request; read its error log file for more information. The reason 1427, and state 31, can be of use for diagnostics by Microsoft. This is a transient error hence retrying the request is likely to succeed. Correct the cause if any and retry.

错误信息可以知道，应该是收不到请求

然后到镜像服务器去查看镜像信息

SELECT DB_NAME(database_id) AS ‘DatabaseName‘
, mirroring_role_desc AS ‘DatabaseRole‘
, mirroring_role_sequence AS ‘FailoverCount‘
, mirroring_partner_instance AS ‘MirroringInstance‘
, mirroring_state_desc AS ‘MirroringState‘
, mirroring_connection_timeout ‘MirroringConnectionTimeoutInSeconds‘
, mirroring_witness_name AS ‘WitnessInstance‘
, mirroring_witness_state_desc AS ‘WitnessState‘
FROM master.sys.database_mirroring
WHERE mirroring_guid IS NOT NULL

发现有些数据库没有证人服务器设置

知道问题后，赶紧恢复

The server instance Witness rejected configure request; read its error log file for more information. The reason 1427, and state 31, can be of use for