I've heard some negative feedback from a colleague regarding an non EMC data dedup solutions. As soon as there is less then 30% of less space on the system (70% used) the system is getting really slow. Is there a similar issue with DD as well? Are there any facts to consider regarding availability and performance?
I've been dancing around 90% few times and I could not see much of impact at that time (DD890). I think best practice is to stay below 80%, but up to 90% of usage just before cleanup does its job should be line you should not cross to be safe.
EMC best practice is to stay below 85% or dedupe and compressions suffer. I have been as high as 98% before I saw an actual system performance impact. Dedupe ratio and compression DO take a hit above 85%