Is Backup Really Irrelevant?

Brian Aker writes in his "PostgreSQL to scale to 1 billion users" post:

Backup is irrelevant for those of you who care about this discussion. LVM/ZFS snapshots are the rule of the land.

While I agree with most of Brian's statements in the article, I respectfully disagree with the statement above, especially the bolded part. Copy-on-write snapshots are EVIL for very large databases operating in a high I/O environment and backup, by no means, is entirely irrelevant. Please correct me if I am wrong but it is my understanding that both LVM and ZFS implement copy-on-write snapshots. Backup may be irrelevant for most sites but not for us.

If, however, by "irrelevant" Brian meant that not important in choosing one database over another, I can agree with that. Why? Because no one benchmarks backup methodologies until backup process starts becoming a major PITA.

Backup methods can be a performance killer when dealing with very large databases. If you're interested in finding out why, and more importantly how, ask me at the conference, come to my scaling MySQL and InnoDB on Solaris session, or check on this blog after the conference.

Bad application design won't get you anywhere with PostgreSQL or MySQL

I am so sick and tired of engaging into flame wars comparing MySQL and PostgreSQL especially when people haven't used both databases together. Both databases have their own strengths, however, if your application is not tuned for the underlying database, you are out of help.

Why do people hate MySQL so much without looking under its hood?

In my opinion, none is the right tool for *every* job.

• 5 reasons why you should never use PostgreSQL
  
• PostgreSQL vs. MySQL
• PostgreSQL vs. MySQL vs. Commercial databases
• PostgreSQL vs. MySQL Comparison (Slashdot)
• PostgreSQL or MySQL
  
• Laughing at Homeland Security

I will add more as time goes by and would appreciate other resources discussing MySQL vs. PostgreSQL.