User names can only be eight characters or fewer in AIX version 5.2 and earlier. Starting with AIX version 5.3, IBM increased the maximum number of characters to 255. To verify the setting in AIX 5.3 and later, you can extract the value from getconf:
# getconf LOGIN_NAME_MAX
9
Or use lsattr:
# lsattr -El sys0 -a max_logname
max_logname 9 Maximum login name length at boot time True
To change the value, simply adjust the v_max_logname parameter (shown as max_logname in lsattr) using chdev to the maximum number of characters desired plus one to accommodate the terminating character. For example, if you want to have user names that are 128 characters long, you would adjust the v_max_logname parameter to 129:
# chdev -l sys0 -a max_logname=129
sys0 changed
Please note that this change will not go into effect until you have rebooted the operating system. Once the server has been rebooted, you can verify that the change has taken effect:
# getconf LOGIN_NAME_MAX
128
Keep in mind, however, that if your environment includes IBM RS/6000 servers prior to AIX version 5.3 or operating systems that cannot handle user names longer than eight characters and you rely on NIS or other authentication measures, it would be wise to continue with the eight-character user names.
