removing ttl

[Kireet]

I need to remove the TTL setting from an existing HBase table and remove 
the TTL from all existing rows. I think this is the proper command for 
removing the TTL setting:

alter 't', {NAME => 'cf', TTL => '2147483647'}
After doing this, do I need to rewrite all the existing data to remove 
the TTL for each cell, perhaps using the IdentityMapper M/R job?

Thanks
Kireet