Solution : https://service.sap.com/sap/support/notes/493828 (SAP Service marketplace login required)
Key words : 
\usr\sap\<sapsid>\sys\profile\<sapsid instancename hostname> chapter 4, \usr\sap\<sapsid>\sys\profile\<sapsid>_dvebmgs_<host>, [cdata[dbhost]]>          </strval>         </fld>      </row> change [dbhost], transaction db02 fails            transaction db02 fails, [cdata[cihost]]>          </strval>         </fld>      </row> save, choose start --> settings control panel --> system, communications protocols failed tostart successfully, sap web application server installation onunix, edit user variable dialog box appears, [cdata[mw2mw2]]>          </strval>         </fld>        <fld
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