[kwlug-disc] Server reboot time ...

[Anton Avramov]

On Mon, 2025-10-06 at 16:30 -0400, Khalid Baheyeldin wrote:
> Anton,
> 
> The dmesg command does not keep data across reboots.
> It only shows the data from when the last boot was done. 

True, but sometimes its still a source of information. I've recently
had a similar experience with a cloud provider. 
Anyway you seams to have found half the time in the commend below and
the rest is probably what Chris suggested. 
See my other comment below. 

> 
> The server has two sets of RAID SSDs, but they should be checked on
> boot, not shutting down.
> 
> Ron,
> 
> Here is what systemd-analyze blame reports.
> Not sure if that is across boots, or just the current boot though.
> 
> 2min 145ms systemd-networkd-wait-online.service
>   30.164s apt-daily-upgrade.service
>    3.226s motd-news.service
>    1.738s fstrim.service
>    1.635s munin-node.service
>     757ms fwupd-refresh.service
>     731ms mysql.service

A! systemd-networkd-wait-online.service had mess with me before. 
How many network interfaces do you have on the machine? Either plugged
in or not? 
And what do you use to manage them? systemd-networkd, NetworkManager,
ifupdown or other?

I use systemd-networkd.

Since my clients servers sometimes boot without network I've solved
that problem with just systemctl disable systemd-networkd-wait-
online.service

However some services would not start properly if there is no network
interface available. To resolve this I install networkd-dispatcher and
have scripts to restart/reload services that do not bring hooks in
their packages to resolve networking going up/down. 

Another option is just to create /etc/systemd/system/systemd-networkd-
wait-online.service.d/override.conf file and override the Start
directive to listen only to your main interface like so: 
[Service]
ExecStart=
ExecStart=/lib/systemd/systemd-networkd-wait-online --interface enp6s0


Notice the first ExecStart is not an error, but is used to clear the
current command. Otherwise it would execute both

Hope helps. 
If you are coming tonight to the meting we could discuss more :) 
Cheers

> 
> The ap-daily-upgrade is not something that runs on boot, and 
> would not block anything. 
> 
> But the first entry of "wait online" is kind of suspicious.
> It may mean that 2 minutes of the current boot is wasted 
> until the network is up (however that is assessed).
> 
> The rest is too low to be relevant. 
> 
> John Sellens
> 
> Great point. I have anecdotally noticed this over the years, but 
> never got to measuring them, because once the server is live, 
> the reboots are rare (sometimes we go 500 days without a reboot).
> 
> This server is not yet live, so I got curious ...
> 
> _______________________________________________
> kwlug-disc mailing list
> To unsubscribe, send an email to kwlug-disc-leave at kwlug.org
> with the subject "unsubscribe", or email
> kwlug-disc-owner at kwlug.org to contact a human being.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.kwlug.org/pipermail/kwlug-disc_kwlug.org/attachments/20251006/b01ed636/attachment.htm>