On 03/14/11 15:33, Sylvain Lebresne wrote: > > CASSANDRA-1537 is probably also a partial but possibly sufficient > solution. That's also probably easier than CASSANDRA-1610 and I'll try > to give it a shot asap, that had been on my todo list way too long. > Thanks, eager to see CASSANDRA-1610 someday. What I've been doing the last day has been multiple restarts across the cluster when one node's data/ dir gets to 150GB. restarting cassandra brings the nodes data/ directory down to around 60GB, I see cassandra deleteing a lot of SSTables on startup.
One question, since I use a TTL is it safe to set GCGraceSeconds to 0? I don't manually delete ever, I just rely on the TTL for deletion, so are forgotten deletes an issue? > The rule is this. Say you think that m is a reasonable value for > GCGraceSeconds. That is, you make sure that you'll always put back up > failing nodes and run repair within m seconds. Then, if you always use > a TTL of n (in your case 24 hours), the actual GCGraceSeconds that you > should set is m - n. > > So putting a GCGrace of 0 in you would would be roughly equivalent to > set a GCGrace of 24h on a "normal" CF. That's probably a bit low. > What do you mean by "normal"? If I were to set GCGrace to 0 would risk data corruption? Wouldn't setting GCGrace to 0 help reduce disk space pressure? Thanks, Karl
