Makes perfect sense for O'Brien, DS9 had serious backup issues in the first couple of years

The Forsaken (season 1 episode 17)

  LOJAL: I've been reading the reports of your Chief of Operations, Doctor. They gave me the impression that he was a competent engineer.
  BASHIR: Chief O'Brien? One of the best in Starfleet.
  LOJAL: Then why aren't the backup systems functioning?
  BASHIR: Well, you know, out here on the edge of the frontier, it's one adventure after another. Why don't I escort you back to your quarters where I'm sure we can all wait this out. 

Rivals (season 2 episode 11)

  KIRA: My terminal just self-destructed.
  DAX: What?
  KIRA: I lost an evaluation report I've been working on for weeks.
  DAX: Even the backups?
  KIRA: Even the backups. 

There's a reason to have a backup to the backup by Destiny (season 3 episode 15)