Re: Performance / cluster scaling question

[André Martin]

After waiting a few hours (without having any load), the block number 
and "DFS Used" space seems to go down...
My question is: is the hardware simply too weak/slow to send the block 
deletion request to the datanodes in a timely manner, or do simply those 
"crappy" HDDs cause the delay, since I noticed that I can take up to 40 
minutes when deleting ~400.000 files at once manually using "rm -r"...
Actually - my main concern is why the performance à la the throughput 
goes down - any ideas?