- Chunks
A chunk is the largest unit of physical disk dedicated to database server data storage.
- Pages
A page is the physical unit of disk storage that the database server uses to read from and write to Informix® databases.
- Blobpages
A blobpage is the unit of disk-space allocation that the database server uses to store simple large objects (TEXT or BYTE data) within a blobspace.
- Sbpages
An sbpage is the type of page that the database server uses to store smart large objects within an sbspace. Unlike blobpages, sbpages are not configurable. An sbpage is the same size as the database server page, which is usually 2 KB on UNIX™ and 4 KB on Windows™.
- Extents
An extent consists of a collection of contiguous pages that store data for a given table.
- Dbspaces
A dbspace is a logical unit that can contain between 1 and 32,766 chunks. The database server uses the dbspace to store databases and tables. Place databases, tables, logical-log files, and the physical log in dbspaces.
- Blobspaces
A blobspace is a logical storage unit composed of one or more chunks that store only TEXT and BYTE data.
- Sbspaces
An sbspace is a logical storage unit composed of one or more chunks that store smart large objects.
- Plogspace
A plogspace is a logical storage unit that is composed of one chunk that stores the physical log. When the physical log is in the plogspace, the database server increases the size of the physical log as needed to improve performance.
- Extspaces
An extspace is a logical name associated with an arbitrary string that signifies the location of external data. The resource that the extspace references depends on a user-defined access method for accessing its contents.
- Databases
A database is a logical storage unit that contains tables and indexes. Each database also contains a system catalog that tracks information about many of the elements in the database, including tables, indexes, SPL routines, and integrity constraints.
- Tables
In relational database systems, a table is a row of column headings together with zero or more rows of data values. The row of column headings identifies one or more columns and a data type for each column.
- Table types for Informix
You can create logging or nonlogging tables in a logging database on HCL Informix®. The two table types are STANDARD (logging tables) and RAW (nonlogging tables). The default standard table is like a table created in earlier versions without a special keyword specified. You can create either a STANDARD or RAW table and change tables from one type to another.
- Tblspaces
Database server administrators sometimes must track disk use by a particular table. A tblspace contains all the disk space allocated to a given table or table fragment (if the table is fragmented). A separate tblspace contains the disk space allocated for the associated index.
- Table fragmentation and data storage
The fragmentation feature gives you more control over where the database stores data. You are not limited to specifying the locations of individual tables and indexes. You can also specify the location of table and index fragments, which are different parts of a table or index that are on different storage spaces.
- Amount of disk space needed to store data
To determine how much disk space you require, follow these steps:
- The storage pool
Every instance of the database server has a storage pool. The storage pool contains information about the directories, cooked files, and raw devices that the server can use if necessary to automatically expand an existing dbspace, temporary dbspace, sbspace, temporary sbspace, or blobspace.
- Disk-layout guidelines
The following goals are typical for efficient disk layout:
- Sample disk layouts
When setting out to organize disk space, the database server administrator usually has one or more of the following objectives in mind:
- Logical-volume manager
You can use the logical-volume manager (LVM) utility to manage your disk space through user-defined logical volumes.