Stirring things up for Fedora 33

Posted Jun 30, 2020 9:52 UTC (Tue) by LtWorf (subscriber, #124958)
In reply to: Stirring things up for Fedora 33 by roc
Parent article: Stirring things up for Fedora 33

Fun fact: because on Fedora /tmp is by default mounted on RAM (with a really huge limit), if you download a large .iso file inside /tmp, the OOMkiller can trigger and kill your wayland session.

Now they are putting even more pressure on the RAM, when machines with 8GiB of RAM are still being sold.

Stirring things up for Fedora 33

Posted Jun 30, 2020 12:51 UTC (Tue) by rahulsundaram (subscriber, #21946) [Link] (5 responses)

>if you download a large .iso file inside /tmp, the OOMkiller can trigger and kill your wayland session.

* Earlyoom is the default now and will likely leave the Wayland session intact. It is also very configurable
* You should use /var/tmp instead of /tmp
* You can disable tmp-on-tmpfs. It is a single mount unit - systemctl disable tmp.mount

Stirring things up for Fedora 33

Posted Jun 30, 2020 12:59 UTC (Tue) by mbiebl (subscriber, #41876) [Link] (2 responses)

> systemctl disable tmp.mount

Be careful here. This removes tmp.mount from local-fs.target.wants so it won't be activated during boot via that target. It still can be started via other means though. Typical example are services that use PrivateTmp=yes. A service that uses PrivateTmp=yes will trigger the start of tmp.mount, even when tmp.mount is disabled. There are other ways how tmp.mount can be activated. See
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=783509

Stirring things up for Fedora 33

Posted Jun 30, 2020 13:39 UTC (Tue) by rahulsundaram (subscriber, #21946) [Link] (1 responses)

I generally mask units if I wanted to be really sure but thanks for the note. That is certainly worth keeping in mind.

Stirring things up for Fedora 33

Posted Jun 30, 2020 23:03 UTC (Tue) by Wol (subscriber, #4433) [Link]

I was looking at the systemd docu, for whatever reason, and iirc, if you put /tmp in fstab, those options take precedence. For example, I always create a massive /tmp on tmpfs, but then I'll typically have 50GB or so of swap...

Cheers,
Wol

Stirring things up for Fedora 33

Posted Jul 1, 2020 6:00 UTC (Wed) by LtWorf (subscriber, #124958) [Link] (1 responses)

I'd argue that if you need to do all this tweaking, it might not be such a great default.

Stirring things up for Fedora 33

Posted Jul 1, 2020 12:38 UTC (Wed) by rahulsundaram (subscriber, #21946) [Link]

> I'd argue that if you need to do all this tweaking, it might not be such a great default.

You don't "need" to do any tweaking whatsoever and I don't. I was offering up all the options for you to consider.

Stirring things up for Fedora 33

Posted Jun 30, 2020 22:53 UTC (Tue) by Wol (subscriber, #4433) [Link]

> Now they are putting even more pressure on the RAM, when machines with 8GiB of RAM are still being sold.

Don't you mean 4GB? I'm looking for a replacement for my wife's laptop, and a similar machine comes - brand new - with 4GB soldered and NO expansion slot ...

Cheers,
Wol