Creating Informix chunk files

Informix® chunk files can be cooked files or raw partitions.

Before you begin

For better performance and reliability on production databases, use raw disk partitions.

Only an experienced system administrator should create chunk files. Do not create chunk files on an NFS-mounted partition.

The default space required for the root, temp, and log dbspaces is about 1 MB per user. For the root dbspace the default space required is at least 60 MB, and for the ccm dbspace it is about 2 MB per user. For the default 40 users, the total is about 220 MB. This estimate is only a rough estimate for the initial database chunk. Allocate dbspace generously to permit future growth.

Cooked files

About this task

No action is necessary on your part to use cooked files (for example, set up a file system).

Use the estimates shown to allocate disk space for cooked chunk files:

40 users (default) 220 MB

Raw partitions

About this task

This section summarizes how to set up a raw partition on a new, blank disk that has been formatted. (New disks typically are formatted by their manufacturers.)

Procedure

  1. Partition the disk into the sizes of your choice.
  2. Optional: Create a symbolic link to the raw device; for example, make chunk_name a symbolic link to the raw device.

    root# ln -s raw_device_path chunk_name

    You would use a symbolic link for the following reasons.

    • If you plan to archive Informix Servers using ccmsrv archive, and restore the servers using ccmsrv restore, the restored Informix server configuration must be nearly identical to the archived server configuration. You must restore to the same chunk file path used to archive the server. Using a symbolic link for the chunk file path ensures that the archive and restore paths are identical.
    • Using a symbolic link facilitates changing the chunk file to a different (but at least same size) partition, or to a larger partition.
    • Using a symbolic link means that you do not have problems if the raw partition name changes, for example, if you upgrade the operating system.
  3. Change the ownership, group, and permission of the raw partition path.
    1. root# chown informix chunk_name
    2. root# chgrp informix chunk_name
    3. root# chmod 660 chunk_name
  4. When ccmsrv create prompts for a raw partition name, type the path to the symbolic link for that partition.

    Be sure to reference the correct partition.

    chunk_name

  5. Repeat steps 2-4 for root, temp, log, and ccm.

    For more information about how to partition a raw disk, see the documentation for your operating system.


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