Advanced Cube Design - Professional SQL Server Analysis Services 2005 with MDX - page 469

get things messed up. Most likely though, are security errors; be sure to verify
you have all the correct Firewall settings and Impersonation settings. Imper-
sonation settings are changed in a secondary tab in the Data Source wizard.
Figure 9-71
Storage Modes & Storage Settings
Where you store partition data is just one part of the storage picture; the
mode in which you store it is the other. The storage modes used with Analysis
Services solutions include MOLAP (Multi-dimensional OLAP), ROLAP (Rela-
tional OLAP), and HOLAP (Hybrid OLAP). These storage types were dis-
cussed in some detail way back in Chapter 1 , so this section contains only a
brief review. The main difference between these storage modes concerns
where the data and (or) aggregated fact data is stored. MOLAP is the tradi-
tional storage mode for OLAP Servers and involves keeping both data and
aggregations on the server. This results in fast query response times, but it is
not as scalable as other solutions. ROLAP is the storage mode in which the
data is left in the relational database. Aggregated or summary data is also
stored in the relational database. The key advantage here is that the ROLAP
will scale as well as your relational hardware/software will supportIt can
sometimes result in slower queries, though. The HOLAP storage mode com-