Uptimes

  • Everybody [and their cats and dogs] claim to have the famous 99.999%. What does this mean?
ClassPercentageYearly downtime
2 nines99%3.7 days
3 nines99.9%8.8 hours
4 nines99.99%53 minutes
5 nines99.999%5.3 minutes
  • You can always claim, but can you prove it?
  • A few old studies [nothing current] claim that there are on average 2 outage per year.
  • So, how do you test? [Try it 1st on a test server, then when you can repeat it, try it finally on a production server].
    1. You pull out one of the drive! Does your database survives?
    2. You shutdown one of the database server! Does your database survives?
    3. You shutdown the network switch that is connected to your database! Does your database survives?

I only mentioned the database, not the server, the database is the import one.

You must address the 3 type of failures:

  1. The computer hardware
  2. The computer software
  3. The network

Now review the uptime/downtime table. Do you still claim the 5 nines?

Applies to:

  • Microsoft SQL Server 2000
  • Microsoft SQL Server 2005
  • Microsoft SQL Server 2008
  • all other SQL Servers