At Thu, 09 Apr 2009 10:38:08 -0500 CentOS mailing list centos@centos.org wrote:
Robert Heller wrote:
At Thu, 09 Apr 2009 07:49:30 -0400 CentOS mailing list centos@centos.org wrote:
What is the rule of thumb for reboots after updates...
Certainly if I update from 5.2 to 5.3 I reboot.
But if you update something like krb5 or pam does that require a reboot? Does the "fix" get automatically loaded and used or do you just do a reboot always?
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.