[codetrotter]

The next sentence suggested that the cause of the problem in this probably hypothetical situation might be “a cronjob kicking off and hogging disk IO for a few minutes”.

So in that case, I guess either run the job with a lower priority and see if that helps, or execute the job more often so it doesn’t have to catch-up all at once one time per week, or rewrite it so that it performs I/O with smaller chunks of data at a time and sleeps for a little while in-between reading or writing chunks of data. Basically, do something so that you no longer have this one huge job consuming all of the IO bandwidth for several minutes every week.