Caveats when upgrading from RHEL 5.4 to RHEL 6.3 on hundreds of production servers [duplicate]
Possible Duplicate:
Caveats when upgrading from Java 6 to Java 7 on hundreds of production servers
I am about to upgrade the RHEL version from RHEL 5.4 to RHEL 6.3 in a few hundreds of production servers.
The upgrade will be tested on a staging environment on virtual machines before production deployment.
Are there any backward-compatibility issues with RHEL upgrades?
I wouldn't run the upgrade process this way if you're planning to perform in-place transitions from EL5 to EL6. It's not an easy or clean process.
See: Why is it so difficult to upgrade between major versions of Red Hat and CentOS? and Upgrade CentOS 5.x to CentOS 6.x - tips and techniques
However, you have the right idea of testing this in a limited-capacity first.
Regardless of deployment technique, the biggest issues I saw in moving from EL5 to EL6 were:
- Dealing with deprecated packages
- Needing a much larger
/bootpartition (from 100Mb to 300Mb) - A large amount of performance tuning needed to deal with the newer scheduling algorithms, different kernel and
sysctldefaults, etc. - Learning about the tuned-adm framework. Also see: Openfiler iSCSI performance