Pages in SQL Server MDF and NDF databases

In SQL Server MDF and NDF databases, all the data and the meta data(that is, the data used to manage other data) are allocated as 8KB pages, as follows:

Page Type Description
Data Page Store record data in the database
Index Page Store clustered and non-clustered indexes
GAM Page Store global allocation map(GAM) info.
SGAM Page Store shared global allocation map(SGAM) info.
IAM Page Store index allocation map(IAM) info.
PFS Page Store PFS allocation info.