centos5 Upgrade Options and process recommendations (from centos3,4,5/beta)

windsea

想很多兄弟未必会看release note，从里面转了下如何升级到centos5，有兴趣的可以看看。

The best and most recommended way to get your existing CentOS-3/CentOS-4
machine running CentOS-5 is to update the machine via the installer.
This involves booting the machine with the install media, and running a
normal installation path. You will be given an option to upgrade the
machine if an older CentOS install is found on the installable
harddrive. You will still need to check for rpm orphans once the machine
has booted into CentOS-5. Packages from non-CentOS repositories might
need special attention.

There is a wiki page starting now at http://wiki.centos.org/Migration/5
to document the process's and experiences of people - so as to create a
single combined knowledge base about updating to CentOS-5 from
CentOS-3/4 as well as from other Distributions. So do join in and
contribute.

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Online Upgrade from CentOS-5/Beta :

We recommend a fresh install, however it should be possible to in-place
update a machine from CentOS-5/Beta to CentOS-5.0/Final using the
folloing steps:

step-1) init 3
step-2) yum clean all;
step-3) yum --disablerepo=* --enablerepo=base --enablerepo=updates
update yum* rpm*
step-4) yum clean all;
step-5) yum --disablerepo=* --enablerepo=base --enablerepo=updates upgrade

For the final step, you should do an 'upgrade' rather than an 'update'.
The yum man page has details on the differences between upgrade and
update options. Also, its important to init 3 before doing the yum
update in order to work around the dbus restart issues that have been
widely reported. And doing the main update using the newer yum can
result in upto 4 times faster update speeds, so its recommended that you
first update yum and rpm.

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Online Upgrade from CentOS-4/Final

The best way to move from CentOS-4 to CentOS-5 is via an installer
upgrade. However if you must do it online, here are some tips to help:
- Remove as many packages as you can, strip it right back to the
original OS if possible
- Backup everything
- Disable all repositories, except the centos-5 OS and Updates repos
- init 3
- shutdown as many services as possible
- download and install the centos-release-5.x rpm, which will update
your yum configs
- run a yum upgade ( not update )

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Online Upgrade from CentOS-3/Final

Online upgrades from CentOS-3 are not recommended. The CentOS Wiki has
some details and examples from tests done by members of the centos-qa
team and if you really *must* upgrade a machine running CentOS-3 to
CentOS-5, I recommend you start with those notes. Feel free to
contribute your experiences there.

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chinabiue

前几天在
http://linuxat.cublog.cn
上我有翻译过这一篇,水平有限...