AIX Tip of the Week

Choosing Between AIX 5 32 and 64 Bit Kernet

Audience: Systems Administrator

Date: May 12, 2002

When you install AIX 5, you can choose either a 32 or 64 bit kernel. In most cases, the choice isn't critical. Here's the similarities and differences.


Both 32 and 64 bit kernel support 64 bit applications Both support JFS2 (large filesystems)


The 64 bit kernel supports over 96 GB memory.

My recommendation is to install the 32 bit kernel, unless you're using JFS2 or need to support over 96 GB memory. The 32 bit kernel has been around longer, and internal benchmarks show comparable performance to the 64 bit kernel. On the other hand, I understand the 64 bit kernel runs JFS2 better.

Bruce Spencer,