Some manufacturers recently have made an impact with a “five nines” uptime guarantee, so I thought I’d provide some perspective.

Most recently, I’ve come in contact with Hitachi’s guarantee. I quickly checked with a few other manufacturers (e.g. Dell EqualLogic) to see if they offer that guarantee for their storage arrays, and many do…but realistically, no one can guarantee uptime because “uptime” really needs to be measured from the host or application perspective. Read below for additional factors that impact storage uptime.

Five Nines is 5.26 minutes of downtime per year, or 25.9 seconds a month.

Four Nines is 52.6 minutes/year, which is one hour of maintenance, roughly.

Array controller failover in EQL and other dual controller, modular arrays (EMC, HDS, etc.) is automated to eliminate downtime. That is really just the beginning of the story. The discussion with my clients …