Points to Note Before Installing Informix

The following sections discuss some important tasks that need to be noted before you install Informix.

$INFORMIXDIR Directory

• On Shared Disks:

When Informix Dynamic Server is installed on shared disks ($INFORMIXDIR), each system must have the same mount point directory for the shared file system. If multiple Informix database servers are defined for a single cluster configuration, each database server must have its own disks and unique mount point directories.

• On Non-Shared Disks:

If the $INFORMIXDIR directories are located on local or non-shared disks, the $INFORMIXDIR/etc/sqlhosts file on each system must contain entries for all Informix database servers.

$ONCONFIG File

• The $ONCONFIG file must be available on each system.
• If the configuration is supporting multiple database servers on a single host, the SERVERNUM defined in the file $INFORMIXDIR/etc/$ONCONFIG must be unique for each server.

Informix Dynamic Server Libraries

The following procedure is not necessary for Informix Dynamic Server version 9.2 or later.

Informix Dynamic Server libraries must be linked from /usr/lib to the libraries in the $INFORMIXDIR/lib directory, and on all machines within the Informix service group's SystemList. Perform the following steps to verify that all libraries have symbolic links.

1. To get a list of the Informix Dynamic Server libraries, look in Informix's /lib directory. For example, if $INFORMIXDIR is /informix, type the following command to find a list of libraries:
     # ls /informix/lib

   Output resembles:

   
     ipldd07a.so  ismdd07b.so  sqlrm
2. For each file in that directory, verify that a link from /usr/lib exists. If a link does not exist, you must create it. The following example shows that a link from /usr/lib exists for the file ipldd07a.so:
     # ls -l /usr/lib/ipldd07a.so

   Output resembles:

   
     lrwxrwxrwx   1 root other 25 Mar 21 15:01
           /usr/lib/ipldd07a.so -> /informix/lib/ipldd07a.so

   If the link is nonexistent, use the following command to create it:

   
           # ln -s /informix/lib/ipldd07a.so /usr/lib/ipldd07a.so

Database Dbspaces

• All database dbspaces of each system, including root and user, must be located on the Informix database server's own set of shared disks.
• If the dbspaces are created using regular (UFS or VxFS) files, the file systems containing these files must be located on shared disks. Create the same file system mount points on each system.
• If you are using raw devices on shared disks for dbspaces, change the permissions, or access mode, on the disk groups storing the Informix Dynamic Server data. Change the permissions for informix to 660.

Transparent Informix Dynamic Server Failover

• To enable Informix Dynamic Server clients to reconnect after a system switch without reconfiguring, include at least one IP resource in the service group for the Informix resource. The hostname mapping the IP address of this resource must be used for the Hostname field in the file $INFORMIXDIR/etc/sqlhosts.
• If you are using the TCP/IP protocol for Informix Dynamic Server client/server communication, verify that the file /etc/services on each system defined in the service group's SystemList attribute contains entries for the service name of the Informix database server. The service name is the fourth field in the file $INFORMIXDIR/etc/sqlhosts, and must match one entry in the /etc/services file. For details on sqlhosts and adding entries to the service name, see the Informix Dynamic Server documentation.