> I am using TTL 3 hours and GC grace 0 for a CF. I have a normal CF that has > records with TTL 3 hours and I dont send any delete request. I just wonder > if using GC grace 0 will cause any problem except extra Memory/IO/network > load. I know that gc grace is for not transferring deleted records after a > down node comes back. So I assumed that transferring expired records will > not cause any problem. > > Do you have any idea? Thank you!
If you do not perform any deletes at all, a GC grace of 0 should be fine. But if you don't, the GC grace should not really be relevant either. So I suggest leaving GC grace high in case you do start doing deletes. Columns with TTL:s will disappear regardless of GC grace. If you do decide to run with short GC grace, be aware of the consequencues: http://wiki.apache.org/cassandra/Operations#Dealing_with_the_consequences_of_nodetool_repair_not_running_within_GCGraceSeconds -- / Peter Schuller (@scode, http://worldmodscode.wordpress.com)
