It has turned out to be a real pain in the *ss.
I see servers without having memory pressure since 20-50% of their memory is shown as cached and not us active and I have mysql going to swap and writing even 500mbyte taking the disk into death.
I have also found many people which have the same issues.
Offcourse some ammount of swap is good for emergency but every crash I have suffered over the last 3 years is due to swap.
A nice article explaining the numa arch.
Code: Select all
http://jcole.us/blog/archives/2010/09/28/mysql-swap-insanity-and-the-numa-architecture/