Scott Silva wrote:
>
>>>> You only *really* need to reboot if/when you update the kernel. Yum/RPM
>>>> takes care of restarting daemons, etc. during the update process. This
>>>> is NOT MS-Windows....
>>> Yes, but any program that is already running will keep using the old
>>> versions of the program, libraries, open files, etc., retaining the disk
>>> space and not sharing the in-memory copy with new instances that start
>>> after the update. And since modern programs like to dynamically load
>>> library modules as needed while running you can get a strange mix of
>>> old/new versions running at once.
>> Generally, this is not as bad as it seems. In some cases, some updates
>> do restart critical daemons (rpm -hUv glibc... will restart sshd for
>> example). Also, since most critical library updates also imply a similar
>> update for the deamons/programs that use those libraries and since the
>> rpms for the deamon programs do restart the deamon they install/update,
>> in most cases the deamons do get restarted at some point during the
>> update process -- that is, since httpd (Apache) depends on apr and when apr
>> gets a critical update, it is very likely that the httpd program would
>> also be rebuilt as well, so that both rpms are updated in the repo. A
>> 'yum update' will install the new apr rpm, then the new httpd rpm and at
>> that point restart httpd, this picking up the new apr library.
>>
>>
> Sometimes you just have to know your system. Like if you update a sendmail
> milter, you would need to restart sendmail also, but if the rpm developer
> didn't write that into the %post section you would want to do it yourself.
You have some chance of 'knowing' the server side of things - a lot less
about what other users might be running. What should you expect if you
have logged in users over freenx, remote X or at the console running
(say) firefox through an update? Or other long running applications,
especially in languages likely to dynamically load new components.
And in one case, I got kicked off of my ssh connection in mid-update.
I'm still not sure what happened there but I had to install yum-utils
and run yum-recover-transaction to continue.
--
Les Mikesell
lesmikesell at gmail.com