I just got a mail from Linode saying that my account "has exceeded the notification threshold (1000) for disk io rate by averaging 1017.36 for the last 2 hours. "
My question is just out of curious: From the literal meaning, disk io rate must mean the rate of read/write to the server's disk. But because I've never got any notification like this during the past few years, I am interested in knowing what has caused this and what it has to do with my website.
Does pageview generate disk i/o? Does download generat disk i/o? Or only literally copying or creation of files generate it? And is it related to my website's overall performance and popularity?
I just want a brief introcution so I can research further by myself, detailed explanation is appreciated but not necessary.