Solution : https://service.sap.com/sap/support/notes/356828 (SAP Service marketplace login required)
Summary : 
      This SAP Note details the migration process of 32-bit SAP systems to a 64-bit architecture on AIX, Solaris, and Linux x86_64. The migration is feasible with the 64-bit 4.6D kernel supported for specific SAP versions including R/3 4.6B/C, BW 2.0B/2.1C, and APO ≥ 3.0A. From SAP Basis Release 6.10 onward, utilizing a 64-bit database on these platforms is imperative as 32-bit kernels are unsupported post-2003. Migration prerequisites stipulate a minimum DB2 Version 7; however, for combined use of 32-bit and 64-bit applications, DB2 Version 8 is required. The note suggests thorough system backups pre-migration and adhering to specific configurations detailed for DB2 installations based on AIX adjustments.
Key words : 
cd /sapmnt/<sapsid>  mv exe exe_32  mkdir exe   mv profile profile_32   mkdir profile   cp profile_32/ profile 4, cd /sapmnt/<sapsid>/exe  /<cd_m>/unix/<ops>/sapcar -xvf /<cd_m>/unix/<ops>/sapexe, sar  /<cd_m>/unix/<ops>/sapcar -xvf /<cd_m>/unix/<ops>/sapexedb, sar  /<cd_m>/unix/<ops>/sapcar -xvf /<cd_m>/unix/<ops>/dbatools, cd /usr/sap/<sid>/sys/exe/run, su root  cd /sapmnt/<sapsid>/exe, adapter1_name db2<sapsid>  adapter2_name db2<sapsid>, /usr/lpp/db2_07_01/instance/db2iupdt -, /usr/opt/db2_08_01/instance/db2iupdt -, sap strongly recommends creating
Related Notes : 
       
| 637842 | DB6: 64-bit DB2 database server with R/3 3.1I, 4.0B, 4.5B | 
| 595304 | DB6: Availability of the 32bit kernel for Release 6.20 | 
| 546900 | DB6: Restoring a 32-bit backup to a 64-bit instance | 
| 544274 | FAQs: DB2/UDB 64-bit support | 
| 531608 | DB6: DB2 Version7 - accessing 64-bit DB from a 32-bit client | 
| 500990 | DB6: SQL1707N during migration to 64-bit | 
| 490247 | DB6: Migrating from AIX 4.3.3 to AIX 5 with DB2 Version 7 | 
| 481697 | Local DB Dir migration for DB <SID> failed | 
| 422467 | DB6: Installation of a 64-bit SAP System | 
| 410252 | DB6: Installing the Latest 4.6D DB2 Admin Tools | 
| 318846 | Installing the 4.6D kernel in 4.6A/B/C SAP systems | 
| 205074 | Installation SAP R/3 64-bit kernel for AIX | 
| 146528 | Configuration of R/3 on hosts with much RAM | 
| 146289 | Parameter Recommendations for 64-Bit SAP Kernel | 
| 103747 | Performance: Parameter recommendations as of Release 4.0 |