> On Nov 24, 2010, at 6:27 PM, mcclnx mcc wrote: > > This server used to run under CENTOS 3.9 X86 and No problem. Due to application can not use CENTOS 3.9 we need upgrade to CENTOS 4 or 5. > > > > If I re-install it and use CENTOS 4.8 X86, will problem gone or not? You may find that CentOS 4.8 x86 with the hugemem kernel will work for you. CentOS 5 no longer supports the hugemem kernel. >From the release notes: http://www.centos.org/docs/4/html/release-notes/as-x86/ Red Hat Enterprise Linux 4 includes a kernel known as the hugemem kernel. This kernel supports a 4GB per-process user space (versus 3GB for the other kernels), and a 4GB direct kernel space. Using this kernel allows Red Hat Enterprise Linux to run on systems with up to 64GB of main memory. The hugemem kernel is required in order to use all the memory in system configurations containing more than 16GB of memory. The hugemem kernel can also benefit configurations running with less memory (if running an application that could benefit from the larger per-process user space, for example.) -- Charles Polisher