Regardless of the logical page size it is configured for, Adaptive Server allocates space for objects (tables, indexes, text page chains) in extents, each of which is eight logical pages. That is, if a server is configured for 2K logical pages, it allocates one extent, 16K, for each of these objects; if a server is configured for 16K logical pages, it allocates one extent, 128K, for each of these objects.
This is also true for system tables. If your server has many small tables, space consumption can be quite large if the server uses larger logical pages.
For example, for a server configured for 2K logical pages, systypes – with approximately 31 short rows, a clustered and a non-clustered index – reserves 3 extents, or 48K of memory. If you migrate the server to use 8K pages, the space reserved for systypes is still 3 extents, 192K of memory.
For a server configured for 16K, systypes requires 384K of disk space. For small tables, the space unused in the last extent can become significant on servers using larger logical page sizes.
Databases are also affected by larger page sizes. Each database includes the system catalogs and their indexes. If you migrate from a smaller to larger logical page size, you must account for the amount of disk space each database requires.