Good post by Brian Betts (thank you) over at El Reg
Once upon a time pretty much the only thing a storage manager had to worry about was running out of capacity.
Disk space was expensive and a slew of products offered data compression, moving disused files off to tape and so on.
Disk space is pretty cheap now, with multi-terabit drives readily available along with petabyte-class storage arrays, and the challenge has shifted first to storage I/O performance and then to application response time.
Read on here