Jeeth,
I would not use the classical archiving in BW but switch right away to the NLS (Near Line). With ADK based archiving the DATA has to be reloaded (see note 1652907).
SAP now offers this in conjunction with Sybase IQ as a storage system. The NearLine data will be available for reporting without reloading.
Sybase IQ will compress the Data ( 70-90% ) with a performance equal or better than the traditional row oriented databases.
Please check note 796393 for compatible Netweaver releases.
When migrating to HANA the NLS storage will run seamlessly with the new HANA DB.
http://scn.sap.com/docs/DOC-54468
Best Regards
Stefan
Practice Engineer ILM