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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 Guide
The Informix® Administrator's Guide provides the information required to administer HCL Informix.
Disk, memory, and process management
Manage shared memory
Monitor shared memory
These topics describe how to monitor shared-memory segments, the shared-memory profile, and the use of specific shared-memory resources (buffers, latches, and locks).
Monitor shared-memory segments
Monitor the shared-memory segments to determine the number and size of the segments that the database server creates.

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.
    - The database server
    - Disk, memory, and process management
      - Virtual processors and threads
        These topics describe virtual processors, explain how threads run within the virtual processors, and explain how the database server uses virtual processors and threads to improve performance.
      - Manage virtual processors
        These topics describe how to set the configuration parameters that affect database server virtual processors, and how to start and stop virtual processors.
      - Shared memory
        These topics describe the content of database server shared memory, the factors that determine the sizes of shared-memory areas, and how data moves into and out of shared memory.
      - Manage shared memory
        Set operating-system shared-memory configuration parameters
        Several operating-system configuration parameters can affect the use of shared memory by the database server.
        Set database server shared-memory configuration parameters
        You can modify the configuration parameters that affect the resident, buffer pool, or virtual portion of shared memory.
        Set SQL statement cache parameters
        There are different ways that you can configure the SQL statement cache.
        Set up shared memory
        To set up shared memory, take the database server offline and then online.
        Turn residency on or off for resident shared memory
        You can turn residency on or off for the resident portion of shared memory.
        Add a segment to the virtual portion of shared memory
        You can use the -a option of the onmode utility to add a segment of specified size to virtual shared memory.
        Reserve memory for critical activities
        You can reserve a specific amount of memory for use when critical activities (such as rollback activities) are required and the database server has limited free memory. This prevents the database server from crashing if the server runs out of free memory during critical activities.
        Configure the server response when memory is critically low
        You can configure the actions that primary or standard database server takes when memory is critically low. You can specify the criteria for terminating sessions based on idle time, memory usage, and other factors so that the targeted application can continue to process. Low-memory responses are useful for embedded applications that have memory limitations.
        Monitor shared memory
        These topics describe how to monitor shared-memory segments, the shared-memory profile, and the use of specific shared-memory resources (buffers, latches, and locks).
        Monitor shared-memory segments
        Monitor the shared-memory segments to determine the number and size of the segments that the database server creates.
        Monitor the shared-memory profile and latches
        Monitor the database server profile to analyze performance and the use of shared-memory resources.
        Monitor buffers
        You can obtain both statistics on buffer use and information about specific buffers.
        Deleting shared memory segments after a server failure
        You must close shared memory segments after a database server failure.
      - Data storage
        The database server uses physical units of storage to allocate disk space. It stores data in logical units. Unlike the logical units of storage whose size fluctuates, each of the physical units has a fixed or assigned size that is determined by the disk architecture.
      - Manage disk space
        You can use several utilities and tools to manage disk spaces and the data that the database server controls.
      - Moving data with external tables
        You can use external tables to load and unload database data.
      - Storage space encryption
        You can encrypt storage spaces (dbspaces, blobspaces and smart blobspaces) with Informix Dynamic Server. The data in encrypted storage spaces is unintelligible without the encryption key. Encrypting storage spaces is an effective way to protect sensitive information that is stored on disk.
    - Logging and log administration
    - Fault tolerance
    - High availability and scalability
      A successful production environment requires database systems that are always available, with minimal if any planned outages, and that can be scaled quickly and easily as business requirements change.
    - Distributed data
    - Overview of automatic monitoring and corrective actions
      You can use the SQL administration API, the Scheduler, and drill-down queries to manage automatic maintenance, monitoring, and administrative tasks.
  - 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.
  - 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.

Monitor shared-memory segments

Monitor the shared-memory segments to determine the number and size of the segments that the database server creates.

The database server allocates shared-memory segments dynamically, so these numbers can change. If the database server is allocating too many shared-memory segments, you can increase the SHMVIRTSIZE configuration parameter. For more information, see the topics about configuration parameters in the Informix® Administrator's Reference.

The onstat -g seg command lists information for each shared-memory segment, including the address and size of the segment, and the amount of memory that is free or in use. For an example of onstat -g seg output, see information about the onstat utility in the Informix® Administrator's Reference.