Creating an Informix database server

About this task

Create at least one Informix® database server.

You can create a database server on the installation computer or on a remote host. Installers often create a database server on the installation computer; however, you are not required to do so. You can make any host a database server if the computer meets the system requirements. A valid installation directory for that platform must also be visible (for example, local or NFS-mounted).

For example, if the installation directory for Oracle Solaris is /usr/local/ccm72 on the solaris1 computer and you want to create a database server on solaris2, you can NFS-mount the installation directory on solaris2, and then create a database server on solaris2. Creating the database server automatically adds an entry for solaris2 to the sqlhosts file in the $CCM_HOME/informix/etc directory.

You can also have a database server run server processes for a different type of platform. For more information, see Adding computers and protocols to the sqlhosts files.

Note: If you create the database server on a different computer than the installation computer, be sure that the database server is correctly configured. For more information, see Routing, services, hosts, passwords, and groups.

Procedure

  1. Log on to the database server computer as user root.

    If your database server computer is the same as your installation computer, you are already logged on as root.

  2. If your database server computer is not the same as your install computer, you must run ccm install -l.
  3. Create a directory for the Informix dbspace (chunk files).

    When you create chunk files, keep in mind:

    • The Informix server limits the size and offset of each chunk file to 2 GB. To work around these limits, break up your raw device into many partitions of 2 GB.
    • Place the chunk files where no one can remove them. If chunk files are moved, the database server will no longer work, and it might lose data.
    • Create the chunk file directory (for example, /data/informix_chunkfiles) on the computer where the Informix server runs. Chunk files must not be on Network File Systems.
    • For the best performance and reliability, use raw partitions for Informix chunk files. If file system corruption occurs, cooked files are affected but raw files are not.
    • The names of your chunk file paths must be fewer than 66 characters.
    Note: Do not put the Informix chunk files directory under the installation directory (ccm_home), or under the ccm_root or informix home directory. These Informix data files must not be backed up as normal UNIX files.
    root# mkdir informix_chunkfiles
    root# chown informix informix_chunkfiles
    root# chgrp informix informix_chunkfiles
    root# chmod 770 informix_chunkfiles
  4. Create a directory for the Rational® Synergy databases (for example, /data/ccmdb).
    Note: To avoid losing files when you upgrade, do not put the database directory under the installation directory.
    root# mkdir ccmdb
    root# chown ccm_root ccmdb
    root# chgrp ccm_root ccmdb
    root# chmod 755 ccmdb
  5. Create the database server.

    If you have already planned specific partitions and sizes, use these paths and sizes to respond to the prompts.

    If you have not planned specific partitions and sizes, use the informix_chunkfiles directory when prompted for the primary chunk path for the root dbspace. Use the defaults for everything else except the number of users. Set the number of users to the expected number of simultaneous users of all databases on this server, rounded up to the nearest 10. Typically, the minimum space required is as follows:

    • log and temp dbspaces are each approximately 1.0 MB per user.
    • root dbspace must be at least 60 MB.
    • ccm dbspace is approximately 2 MB per user.

    For the default of 40 users, the total is approximately 220 MB. The default is only a rough estimate for the initial database chunk. In general, generously allocate dbspace to permit for future growth.

    The directory that contains the chunk files must be owned by informix, group informix, and mode 770.

    When prompted, enter the values for your number of processors , number of users, and server number.

    Note: If you have other Informix installations, either active or inactive, the default server number that ccmsrv create attempts to use might already be in use. An error such as this appears in the log file:
    11:13:05  shmget: [EEXIST][17]: key 52574801: shared memory already exists
    11:13:05  mt_shm_init: can't create resident segment

    Correct this problem by using a different server number.

    If you must increase the size of your shared memory kernel parameters, you might also see an error like the following in the log file:

    16:53:12  shmat: [EMFILE][24]: out of shared memory segments, check system SHMSEG
    16:53:12  mt_shm_init: can't create resident segment

    To learn more about shared memory kernel parameter values, see Check shared memory and semaphore kernel parameters.

    Answer Y when you are prompted to create the database server. Use the UNIX commands appropriate for your shell.

    Note: If you have set up raw partitions, you are prompted for a raw partition path when you run the ccmsrv create command. In such cases, type the path to the device file for that partition. Be sure to reference the correct partition and offset.
    root# su - informix               Password:*****
    $ CCM_HOME=ccm_home; export CCM_HOME
    $ PATH=$CCM_HOME/bin:$PATH; export PATH
    $ ccmsrv create -s servername
    $ exit

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