SQL Server Extents, PFS, GAM, SGAM and IAM and related corruptions


I’m going to start a series of posts talking about SQL Server allocation pages and corruption. Each post will have samples showing how SQL Server use these pages and scenarios of corruption.

The first post will talk about the Extents, PFS, GAM, SGAM and IAM and related corruptions, you can find all concepts from following two pages:

Pages and Extents Architecture Guide

Under the covers: GAM, SGAM, and PFS pages

 

As there are many concepts and samples, I’m going to discuss the topics in two or three posts.

 

1.Extents

Extents are the basic unit in which space is