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Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
System administration
These topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL Informix® database servers.
Administrator's Reference
The Informix® Administrator's Reference includes comprehensive descriptions of HCL Informix configuration parameters, the system-monitoring interface (SMI) tables in the sysmaster database, the syntax of database server utilities such as onmode and onstat, logical-log records, disk structures, event alarms, and unnumbered error messages.
Configuring and monitoring Informix®
Disk Structures and Storage
Dbspace Structure and Storage
Structure of the Chunk Free-List Page

Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
- System administration
  These topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL Informix® database servers.
  - List of utilities
    HCL Informix® includes utilities and applications that you can use to perform administrative tasks and capture information about configuration and performance.
  - Administrator's Guide
    The Informix® Administrator's Guide provides the information required to administer HCL Informix.
  - Administrator's Reference
    The Informix® Administrator's Reference includes comprehensive descriptions of HCL Informix configuration parameters, the system-monitoring interface (SMI) tables in the sysmaster database, the syntax of database server utilities such as onmode and onstat, logical-log records, disk structures, event alarms, and unnumbered error messages.
    - Configuring and monitoring Informix®
      - Database configuration parameters
        The Informix® database server uses a configuration file, which is called the onconfig file, during initialization. This file contains default configuration parameter values. You can modify the parameter values to improve performance and other characteristics of the instance or database.
      - The sysmaster database
        These topics describe the sysmaster database and provide reference information for the system-monitoring interface (SMI).
      - The sysadmin Database
        The sysadmin database contains the tables that contain and organize the Scheduler tasks and sensors, store data collected by sensors, and record the results of Scheduler jobs and SQL administration API functions.
      - Disk Structures and Storage
        Dbspace Structure and Storage
        Structure of the Root Dbspace
        As part of disk-space initialization, the database server initializes specific structures in the initial chunk of the root dbspace.
        Reserved Pages
        Structure of a Regular Dbspace
        Structure of the Chunk Free-List Page
        Structure of the Tblspace Tblspace
        Structure of the Database Tblspace
        Structure and Allocation of an Extent
        Structure and Storage of a Dbspace Page
        Structure of Fragmented Tables
        Structure of B-Tree Index Pages
        Structure of R-Tree Index Pages
        Storage of Simple Large Objects
        Sbspace Structure
        An sbspace is similar to a blobspace except that it holds smart large objects.
        Time Stamps
        Database and Table Creation: What Happens on Disk
      - Interpreting Logical-Log Records
    - Administrative Utilities
    - SQL Administration API
    - Appendixes
  - DB-Access User's Guide
    The Informix® DB-Access User's Guide describes how to use the DB-Access utility to access, modify, and retrieve information from Informix database servers.
  - High-Performance Loader User's Guide
    The describes how to use the HCL Informix® to load and unload large quantities of data efficiently to or from Informix databases.
  - Performance Guide
    The Informix® Performance Guide describes how to configure and operate your HCL Informix database server to improve overall system throughput and to improve the performance of SQL queries.
  - SNMP Subagent Guide
    The describes the Simple Network Management Protocol (SNMP) and the software that you need to use SNMP to monitor and manage HCL Informix® database servers and databases.
  - InformixHQ Guide
    InformixHQ is a modern web console for visualizing, monitoring, and managing your Informix server instances. It is purpose built for ease-of-use, scaling out, and optimizing DevOps needs. It provides critical performance management capabilities, monitoring how key performance metrics are changing over time and tracking how efficiently Informix is running your workload even when you’ve stepped away from your screen. Its monitoring system feeds directly into a customizable alerting system so you can be immediately alerted via email, Twilio, or PagerDuty whenever an issue occurs on one of your Informix database server instances. InformixHQ is designed to be scalable to efficiently manage and monitor as many Informix database server instances as you need. Moreover, it's a tool that can be shared by the DBAs, the app developers, the ops engineers, and management and accessed from any desktop, laptop, or mobile device. InformixHQ is the centralized hub for graphical monitoring, alerting, and administration of your Informix database servers.
- Backup and Restore Guide
  The Informix® Backup and Restore Guide describes how to use the Informix ON-Bar and ontape utilities to back up and restore database server data. These utilities enable you to recover your databases after data is lost or becomes corrupted due to hardware or software failure or accident.
- Enterprise Replication
  The HCL® Informix® Enterprise Replication Guide describes the concepts of data replication using Informix Enterprise Replication, including how to design your replication system, as well as administer and manage data replication throughout your enterprise.

Structure of the Chunk Free-List Page

In every chunk, the page that follows the last reserved page is the first of one or more chunk free-list pages that tracks available space in the chunk. For a non-root chunk, the initial length of the free space is equal to the size of the chunk minus three pages. If an additional chunk free-list page is needed to accommodate new entries, a new chunk free-list page is created in one of the free pages in the chunk. Free-List Page illustrates the location of the free-list page.

Use oncheck -pe to obtain the physical layout of pages in the chunk. For more information, see oncheck -ce, -pe: Check the chunk-free list.

begin figure description - The paragraph that precedes this figure describes the content of the figure. - end figure description — Figure 1. Free-List Page