The following is a list of considerations and requirements for configuring and changing user names on the AIX machines in the Data Center.
Each of the AIX systems in the data center has two internal drives. All other storage is on the EMC external drives.
Only one internal drive is utilized for storage, the other internal drive is used as a mirror in case of drive failure. Only the operating system is stored on the internal drives. The internal disk drives will normally be called "hdisk0" and "hdisk1".
The external drives contain all applications, programs, databases, etc.
A file system is a like a drive partition of a specified size. Each AIX system has many file systems which are "mounted" and available for application, database, and user storage.
File systems stored on the external drive will all begin with a directory which matches the host name of the machine where the file system is normally mounted. For example, on the system "mtxdqa01" the CONTROL-M/Agent file system, which is mounted on each AIX server, physically exists on an external EMC drive and has the following directory as a mount point:
/mtxdqa01/bmc/ctmagent
File systems which are on internal drives will all begin with something other than the hostname of the machine on which it is normally mounted.
Each AIX user is assigned a home directory. This is a location where configuration files, work files, etc for each user are stored. Every user must have have a home directory. Normally the mount point of the home file system is:
/home
A users home directory would be a subdirectory off of /home. For example, the home directory of "jdoe00" would normally be:
/home/jdoe00
All of jdoe00's configuration files, work, etc would be stored under that directory location.
All regular users home directory should be stored on external drives. This means that the directory structure for the home directory will begin with the hostname of the machine. For example on the machine "mtxdqa01" the home directory will be configured as:
/mtxdqa01/home
Therefore the home directory of the user "jdoe00" will be:
/mtxdqa01/home/jdoe00
Most of the AIX systems in the Data Center will be configured with High Availability Clustered Multi-Processing (HACMP). This means that each HACMP AIX system will be part of a group which is capable taking over the workload of a failed AIX system.
This capability requires that the users of the failed AIX system be able to login to the running AIX system. This means that not only do the users need to be configured on the system to which they need access, they must also be configured on all systems which are configured to be a failover backup for that system.