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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 disk space
You can use several utilities and tools to manage disk spaces and the data that the database server controls.
Automatic space management
You can configure the server to add more storage space automatically when more space is required. You use space more effectively and ensure that space is allocated as necessary, while reducing out-of-space errors. You reduce the time required to manually monitor your spaces to determine which storage space might run out of free space. If you configure the server to automatically add space, you can also manually expand a space or extend a chunk.
Changing the threshold and wait time for the automatic addition of more space
While Informix® can react to out-of-space conditions by automatically extending or adding chunks when a storage space is full, you can also configure the server to extend or add chunks before a storage space is full.

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
      - 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.
        Allocate disk space
        This section explains how to allocate disk space for the database server.
        Specify names for storage spaces and chunks
        Chunk names follow the same rules as storage-space names.
        Monitor storage spaces
        You can monitor the status of storage spaces and configure how you are notified when a storage space becomes full.
        Manage dbspaces
        This section contains information about creating standard and temporary dbspaces with and without the default page size, specifying the first and next extent sizes for the tblspace tblspace in a dbspace when you create the dbspace, and adding a chunk to a dbspace or blobspace.
        Manage blobspaces
        This section explains how to create a blobspace and determine the blobpage size.
        Manage sbspaces
        This section describes how to create a standard or temporary sbspace, monitor the metadata and user-data areas, add a chunk to an sbspace, and alter storage characteristics of smart large objects.
        Manage the plogspace
        You create or move the plogspace with the onspaces utility or equivalent SQL administration API command.
        Automatic space management
        You can configure the server to add more storage space automatically when more space is required. You use space more effectively and ensure that space is allocated as necessary, while reducing out-of-space errors. You reduce the time required to manually monitor your spaces to determine which storage space might run out of free space. If you configure the server to automatically add space, you can also manually expand a space or extend a chunk.
        Creating and managing storage pool entries
        You can add, modify, and delete the entries in the storage pool.
        Marking a chunk as extendable or not extendable
        You mark a chunk as extendable to enable the automatic or manual extension of the chunk. You can change the mark to not extendable to prevent the automatic or manual extension of the chunk.
        Modifying the sizes of an extendable storage space
        You can control how an extendable storage space in the storage pool grows by modifying the create size and the extend size. By default, the maximum size of an extendable storage space is unlimited. You can limit the size of an extendable storage space by setting a maximum size.
        Changing the threshold and wait time for the automatic addition of more space
        While Informix® can react to out-of-space conditions by automatically extending or adding chunks when a storage space is full, you can also configure the server to extend or add chunks before a storage space is full.
        Configuring the frequency of the monitor low storage task
        You can change the frequency of the mon_low_storage task, which periodically scans the list of dbspaces to find spaces that fall below the threshold indicated by SP_THRESHOLD configuration parameter. If the task finds spaces that below the threshold, the task attempts to expand the space, by extending an extendable chunk or by using the storage pool to add a chunk.
        Manually expanding a space or extending an extendable chunk
        You can manually expand a space or extend a chunk when necessary, instead of waiting for Informix® to automatically expand the space or extend a chunk.
        Example of minimally configuring for and testing the automatic addition of more space
        This example shows how you can minimally configure and then test the automatic addition of more space. You can do this by creating a dbspace, filling the space, adding an entry to the Informix® storage pool, and loading tables into the space. When the space fills, Informix automatically expands it.
        Example of configuring for the automatic addition of more space
        This example shows how you can fully configure for the automatic addition of more space by changing some configuration parameter settings, changing the frequency of a task that monitors low storage, and specifying information for extendable spaces and chunks.
        Drop a chunk
        Use the onspaces utility to drop a chunk from a dbspace.
        Drop a storage space
        Use onspaces to drop a dbspace, temporary dbspace, blobspace, sbspace, temporary sbspace, or extspace.
        Creating a space or chunk from the storage pool
        If your storage pool contains entries, you can create storage spaces or chunks from free space in the storage pool.
        Returning empty space to the storage pool
        You can return the space from an empty chunk or storage space to the storage pool.
        Manage extspaces
        Skip inaccessible fragments
        Display databases
        You can display the databases that you create with SMI tables.
        Monitor disk usage
        Multitenancy
        You can segregate data, storage space, and processing resources for multiple client organizations by creating multiple tenant databases in a single instance of Informix®.
        Storage optimization
        Data compression and consolidation processes can minimize the disk space that is used by your data and indexes.
        Load data into a table
      - 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.

Changing the threshold and wait time for the automatic addition of more space

While Informix® can react to out-of-space conditions by automatically extending or adding chunks when a storage space is full, you can also configure the server to extend or add chunks before a storage space is full.

About this task

Specify a threshold for the minimum amount of free KB in a storage space to trigger a task that expands the space.

You can also use the SP_WAITTIME configuration parameter to specify the maximum number of seconds that a thread waits for a space to expand before returning an out-of-space error.

To change the threshold and wait time:

Procedure

Change the value of the threshold specified in the SP_THRESHOLD configuration parameter from 0 (disabled) to a non-zero value. Specify a value from either 1 to 50 for a percentage of a value from 1000 to the maximum size of a chunk in KB.
Change the value of the SP_WAITTIME configuration parameter, which specifies the maximum number of seconds that a thread waits for a space to expand before returning an out-of-space error.