on 4-9-2009 10:07 AM Les Mikesell spake the following: > 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. > I always run my updates through screen. That way disconnects aren't a problem. During major updates I also usually run yum with the --downloadonly option so I can have most of the files local when I am ready.
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