Originally posted by: janhar

ISSUE: AIX Customer reported coredumps when trying to do cpan update.

ROOT CAUSE: Limitation for perl.rte runtime. AIX does not set maxdata, because of issues this causes for AIX tools using perl.

Originally posted by: janhar

RESOLUTION: The following worked:

# export LDR_CNTRL=MAXDATA=0x80000000@DSA;cpan

Another solution would be to use a perl.rpm version (which AIX Support recommends,  for previously listed reasons) and you could do an ldedit to permanently set this.

# ldedit -b maxdata=0x80000000 "path to perl.rpm perl binary"

Reminder: The perl shipped with AIX in the perl.rte fileset is intended for sole use by the operating system. AIX does not migrate customer-installed modules to this new version, since the modules are not tested by AIX.  They are usually left on the system in a directory left over from the previous version.
 
For example:
 
# ls  /usr/opt/perl5/lib
5.10.1   5.28.1
 
# ls -Ral /usr/opt/perl5/lib/5.10.1/CPAN
total 24
drwxr-xr-x  2 root   system     4096 Jan 27 14:39 .
drwxr-xr-x  3 root   system     4096 Oct 30 15:32 ..
-rw-r--r--  1 root   system     2123 Apr 25 2019 Config.pm
 
 
The Config.pm from 5.10.1 was left on the system, because installp did not know how to uninstall this module.
 
If users have installed modules to perl, they will need to reinstall these modules to the newer perl after an update, if they want to use the AIX perl. AIX cannot recommend that these modules be copied to the new AIX perl location, because they may not be supported by the new perl.rte version. Users are always encouraged to use the latest perl RPM version available on the AIX Toolbox for Linux to ensure they are using the latest versions tested on AIX. Since this perl version will install to a different location, this also gives the user control over any perl updates which could impact their environment.
 
Reference: AIX Perl Updates and Support for perl.rte
https://www.ibm.com/support/pages/aix-perl-updates-and-support-perlrte