How to post and delete system message in sap?

System Message in Sap.
            Occasionally, SAP system will be shut down due to various maintenance activities like kernel upgrade, offline backup, client copy etc. Before doing any of these activities it is best practice to communicate to SAP users that system won’t be available during that time so that users will plan their work accordingly.

Steps for sytem message in Sap.
1.This system message can be posted using SM02 transaction code in SAP.

2.A message like “R3 system unavailable in between10pm to 6 am due to planned Offline Backup activity. Please plan your work accordingly” can be posted to keep the customers informed about the downtime of the system.

3.Go to Transaction SM02 and click on create button as shown below :

4.This pops up another window as shown below. In this window, you can compose the message that is to be published. In that window, you will have to provide details like client number, server name, logon language, expires on, delete on fields as shown below.

5.If specific client is specified in the above window, only users of that client can view the system message posted. If an SAP system consists of more than one application server, you need to select application server on which this message should appear. 

6.Specify expires on field to mention the system when this message should expire so that message won't be visible to users after that. 

7.The delete on field is used to mention the date and time on which the posted message should be deleted from the system. 

8.Incase you would like to delete the system message manually, you can even do so, by selecting the system message and clicking on delete icon as shown below.

9.System prompts to confirm deletion as below.  Message gets deleted if confirmed by pressing Yes button in the below screen.

10.Click yes to conform delete system message.