On Mon, 12 Jan 2004, Simon Perreault <nomis80@xxxxxxxxxxx> wrote: > >On January 12, 2004 18:36, Don wrote: >> But, how do I know what needs to be restarted/rebooted when updates to >> things like cron or glibc are installed? To "be safe" I could always reboot >> the machine after installing updates, but that seems unnecessary and >> certainly unwanted. > >The only time you need to reboot the machine is when you install a new kernel. >All other rebooting is useless. It's not quite that simple. Let's say you update glibc to fix a security hole or a memory leak. That's great, and any program you start after the update will be running with the new glibc. But, all the currently running programs will still be using the old, deleted version of glibc, so services such as sendmail, cups, the X server, etc. don't get the benefit of the change until they are restarted. For something as fundamental as glibc you basically have to bring the system down to single-user mode in order to get rid of all the references to the old version. Offhand, I can't think of anything besides critical libraries and perhaps the X server that would fall into the category of needing special action to restart things after an update. I believe Simon is correct in his statement that only a kernel update actually _requires_ a reboot (yes, there's even a way to restart 'init' without interfering with the rest of the system), but for a few critical pieces rebooting takes less time than figuring out how to avoid the reboot. -- Bob Nichols rnichols@xxxxxxxxxxxxxxx
