On a system with 4 AMPs, you create a database with 1 gigabyte of permanent space. The per-AMP quota of permanent space is 250 megabytes. If you set the permanent space skew limit to 10%, any AMP is allowed a skew limit of 25 megabytes over the per-AMP quota of permanent space. An AMP can use up to 275 megabytes of permanent space as long as total permanent space used does not exceed the 1 gigabyte global limit for permanent space.
CREATE DATABASE d1 AS PERM = 1e9 SKEW = 10 PERCENT;