Looking for opinion on bets way to do file level backup and store the date of site.

Thinking of attaching iscsi lun to the backup server. Using arcserve backup all the data to that lun. replicate the lun to dr site.

is this correct approach or there is a better way of doing it to insure data backup and it is off site.

we are doing approximately 2 TB a week
Looking for some compression so I can keep more than 2 month of data or even 3 month.

Please suggest the best way to accomplish it with Celerra 5.6