<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, May 14, 2019 at 10:24 AM Ulrich Windl <<a href="mailto:Ulrich.Windl@rz.uni-regensburg.de">Ulrich.Windl@rz.uni-regensburg.de</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">>>> Andrei Borzenkov <<a href="mailto:arvidjaar@gmail.com" target="_blank">arvidjaar@gmail.com</a>> schrieb am 14.05.2019 um 08:40 in<br>
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<CAA91j0VyN+972Q+D8b5YO1s04JM0BuxcHz_HN8fq9=-<a href="mailto:H616rXQ@mail.gmail.com" target="_blank">H616rXQ@mail.gmail.com</a>>:<br>
> On Tue, May 14, 2019 at 9:35 AM Ulrich Windl<br>
> <<a href="mailto:Ulrich.Windl@rz.uni-regensburg.de" target="_blank">Ulrich.Windl@rz.uni-regensburg.de</a>> wrote:<br>
> <br>
>><br>
>> I knew that. It doesn't answer _why_ /var/run is obsolete.<br>
>><br>
> <br>
> /var/run needs /var which is not guaranteed to be there when you need<br>
> it which complicates things.<br>
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Thanks,<br>
<br>
I'll start a new thread on this (I wanted to ask anyway):<br>
AFAIK systemd does socket communication a lot, while old init was happy with just a root filesystem.<br>
So I wonder how this Hen-Egg_Problem is solved: Systemd needs a socket to operate, but to provide the infrastructure, systemd would need the socket do do so.<br>
Or expressed in other words: How can systemd create /run when it needs /run to operate?<br></blockquote><div><br></div><div>1. systemd performs these actions during initialization, before switching to the main loop.</div><div>2. systemd can operate without any sockets; it connects to D-Bus for control once it becomes available, but it's not a runtime requirement.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
The corresponding question would be for shutdown: How will systemd unmount /run? OK, if ist a ramdisk, it's not really needed.<br></blockquote><div><br></div><div>The 'systemd-shutdown' binary doesn't unmount /run or /, it keeps the former and remounts the latter read-only.</div><div><br></div><div>(It can optionally pivot_root *to* /run, though, and unmount / using the "shutdown initramfs" feature.)</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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Another related question is that of shutdown in general:<br>
For startup the semantics of Before= and After= are clear, but isn't it just reverted for shutdown? That is if "M" has "After=X" and "Before=Y", does that imply that Y is stopped before M will be stzopped, and M will be stopped before X is?<br></blockquote><div><br></div><div>Yes, it is reversed on shutdown.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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>From the experience how fast shutdown happens, I don't think it's like that.<br></blockquote><div><br></div><div>Usually killing processes is faster than loading them from disk.</div><div><br></div></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr">Mantas Mikulėnas</div></div></div>