Open HANA studio in Diagnosis mode.

If SAP HANA System is down or cannot be reached by SQL connection , the administrative perspective can be opened in Diagnosis mode for troubleshooting.
HANA studio will open diagnosis mode automatically if SAP HANA system is getting stopped or restarted.
SAP HANA uses sapstartsrv to get system information shown in Diagnosis mode.

Requirement: You want to open Diagnosis mode for troubleshooting.
Prerequisite: You need a database user with DATA ADMIN or CATALOG READ system privilege. You also need credentials of <SID>adm user.

Steps:
  • Connect to the required system via HANA Studio
  • Open Administration perspective,  You can open it from Window > Open > Perspective > Administration Console
  • In Administration perspective ,open the "Diagnosis mode" as shown below.
  • It will prompt you for <SID>adm credentials.
SAP HANA Diagnosis mode
Once you enter the <SID>admin credentials , HANA studio will collect all information and will show under following page tabs:
  • Process: Shows the HANA services state.
  • Diagnosis Files: One can access  HANA log/trace files,from here you can create a single zip file for SAP Support.
  • Emergency Information tab: This tab will list connection ,transaction and thread related information here, we can cancel connections and transactions form here.
SAP HANA Diagnosis mode- Process , Diagnosis files and Emergency information
If you are getting below error while opening Diagnosis mode then try following solution options:
"Could not retrieve diagnosis files from all hosts. For more information see Details."

Option 1 : Make sure sapstartsrv process is running at OS level.
Option 2: If sapstartsrv is running but still you are not able to connect , go to HANA Studio > Window > Preferences > General > Network Connection and change the Active provider to DIRECT.
Option 3:If you are connecting to HANA studio using IP address instead of hostname/DNS , make sure you have a IP-Hostname mapping entry in HOSTS files(Windows location - C:\Windows\System32\drivers\etc) of your laptop.

Reference:
http://help.sap.com/