[Slvd] What to restart after system upgrade? When to restart X server?

drrossum · 2011-12-22 18:13:11

Hi all,

After a system upgrade, what should be restarted? The following actions I know about:
kernel (linux): reboot
daemon (sshd, cups, iptables, etc.): rc.d restart ...
application (fvwm, mutt, etc.): restart application

But what will require restarting X server? Can the current X server continue to run after upgrading one the following:
1. xorg-server
2. libx11 or other libraries xorg-server depends on
3. anything else?

I want to keep the system up-to-date but avoid restarting the X server to maintain my X session (>100 windows carfully spread and grouped over 22 workspaces). Unfortunately, there is no xsm anymore and, no, I don't like gnome/kde/thelike.

Thanks,
Daan

Last edited by drrossum (2012-03-26 15:37:37)

GERGE · 2011-12-22 18:28:17

Restart the system for the kernel. For DE updates restarting X might be needed but you can also restart DE itself like Gnome 3 does it.

n0stradamus · 2011-12-22 20:09:04

drrossum wrote:

I want to keep the system up-to-date but avoid restarting the X server to maintain my X session (>100 windows carfully spread and grouped over 22 workspaces). Unfortunately, there is no xsm anymore and, no, I don't like gnome/kde/thelike.

Some window managers implement xsm functionality, i3 being one of them. Until now it is able to save the layout for restarts of itself (e.g. after an update). The possibility to save whole layouts between X restarts is planned. It's definitely worth a look, I'm using it too

.:B:. · 2011-12-22 20:48:50

Openbox e.g. allows for a restart from within a running session.

drrossum · 2011-12-22 21:39:10

Yes, many WM do. I use Xmonad and fvwm which both do too. But my question is about X, not the WM.

When is one _required_ to restart _X server_?

Can one update glibc, xorg-server, etc. and just keep X server running? Or will things start to break within the session?

Perhaps, I should just give it a try, once, and see what happens. But there must be fundamental guidelines for what to restart when updating the system...

Thanks,
Daan

.:B:. · 2011-12-22 21:42:54

You don't need to restart it, just logging in and out is enough. That should restart the X server. I have never seen a running X server break after an upgrade.

drrossum · 2011-12-22 23:07:20

.:B:. wrote:

That should restart the X server

But that's exactly what I'd like to avoid.

.:B:. wrote:

I have never seen a running X server break after an upgrade.

Is the X server that static? Will it never access any dynamically linked libraries after it has started? That'd be cool.

Can anyone confirm whether that is true?

drrossum · 2012-03-24 05:59:57

I've tested "no-restart after upgrade" for a few months:

1) No, X server doesn't break after upgrades - no X restart required!
2) Kernel upgrade doesn't break the system either (except you can no longer modprobe kernel modules) - so no reboot required.
3) Applications/daemons: same thing.

My conclusion so far:
Upgrades are pretty harmless and restarts/reboots are only needed to start using the new version.

Please post any exceptions you encounter!

hadrons123 · 2012-03-24 06:43:37

.:B:. wrote:

You don't need to restart it, just logging in and out is enough. That should restart the X server. I have never seen a running X server break after an upgrade.

If logging in and out restarts the X server, why the PID doesnt change after the restart?
Or am I missing something?

Last edited by hadrons123 (2012-03-24 07:32:32)

Cloudef · 2012-03-24 07:30:09

drrossum wrote:

I've tested "no-restart after upgrade" for a few months:
1) No, X server doesn't break after upgrades - no X restart required!
2) Kernel upgrade doesn't break the system either (except you can no longer modprobe kernel modules) - so no reboot required.
3) Applications/daemons: same thing.
My conclusion so far:
Upgrades are pretty harmless and restarts/reboots are only needed to start using the new version.
Please post any exceptions you encounter!

http://xpra.org/, you could use this if you hate loosing some of your X windows so much

SanskritFritz · 2012-03-24 08:25:21

Cloudef wrote:

http://xpra.org/, you could use this if you hate loosing some of your X windows so much

Wow. Just wow. Thank you!

brebs · 2012-03-24 08:30:35

.:B:. wrote:

I have never seen a running X server break after an upgrade.

I have, but it's surprisingly rare.

A useful command is:

lsof | grep 'DEL.*lib'

I put this line in a script called stalelibs. Helps to see which services should be restarted. Or whether I'll just take the easy option and reboot

Can everyone please learn the difference between "lose" and "loose"? kthx.

SanskritFritz · 2012-03-24 09:09:04

brebs wrote:

Can everyone please learn the difference between "lose" and "loose"? kthx.

I lose when I'm too loose.
Thanks for that one-liner.

Last edited by SanskritFritz (2012-03-24 09:09:53)

drrossum · 2012-03-25 02:44:38

brebs wrote:

A useful command is:
lsof | grep 'DEL.*lib'
I put this line in a script called stalelibs. Helps to see which services should be restarted. Or whether I'll just take the easy option and reboot :)

This is very helpful!

Also, in the link that you sent it is explained why programs don't break when their shared libraries are removed:

Existing programs (that are already loaded) have pointers to the old version, as Naib says, in RAM as code or an inode location as a file handle to the deleted version. Once all handles are gone/programs terminated, the file will then truly be "removed" from the disk and space reclaimed. Until then you'll see shared libraries still eating disk space and RAM, despite them being removed.
This is why it's good to reboot the machine after certain upgrades such as libc, so programs like init can pick up a new copy of libc.

@brebs: Thanks for the great contribution!

Blµb · 2012-03-25 08:36:08

Rather than rebooting you usually want to just kexec into the new kernel - this will only restart the system, without going over the bios etc.
Except rather than parsing grub confs, like in the wiki, I'd just use /proc/cmdline like this (it is also mentioned on the side in the wiki, but whatever):

/sbin/kexec -l \
        --append="`cat /proc/cmdline`" \
        --initrd=/boot/initramfs-linux.img \
        /boot/vmlinuz-linux \
&& init 6

Last edited by Blµb (2012-03-25 08:37:24)

Arch Linux

#1 2011-12-22 18:13:11

[Slvd] What to restart after system upgrade? When to restart X server?

#2 2011-12-22 18:28:17

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#3 2011-12-22 20:09:04

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#4 2011-12-22 20:48:50

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#5 2011-12-22 21:39:10

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#6 2011-12-22 21:42:54

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#7 2011-12-22 23:07:20

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#8 2012-03-24 05:59:57

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#9 2012-03-24 06:43:37

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#10 2012-03-24 07:30:09

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#11 2012-03-24 08:25:21

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#12 2012-03-24 08:30:35

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#13 2012-03-24 09:09:04

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#14 2012-03-25 02:44:38

Re: [Slvd] What to restart after system upgrade? When to restart X server?

#15 2012-03-25 08:36:08

Re: [Slvd] What to restart after system upgrade? When to restart X server?

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