[gentoo-user] Re: /var/tmp on tmpfs

[Kai Krakow <hurikhan77@gmail.com>]

Am Thu, 08 Feb 2018 19:11:48 +0200 schrieb gevisz:

> I never used tmpfs for portage TMPDIR before and now decided to give it
> a try.
> 
> I have 8GB of RAM and 12GB of swap on a separate partition.
> 
> Do I correctly understood
> https://wiki.gentoo.org/wiki/Portage_TMPDIR_on_tmpfs that I can safely
> set in the fstab the size of my tmpfs to 12GB so that the chromium could
> be emerged in tmpfs (using the swap) without the need to set
> notmpfs.conf for chromium and the likes.
> 
> And I am going to set the whole /var/tmp/ on tpmfs instead of just
> /var/tmp/portage Is it ok?

I'm using systemd automounts to discard /var/tmp/portage when there is no
longer a user of this directory. It has one caveat: If you want to
inspect build problems, you should keep a shell running inside.

Here's the configuration:

$ fgrep portage /etc/fstab
none /var/tmp/portage tmpfs noauto,size=150%,uid=250,gid=250,mode=0775,x-systemd.automount 0 0

$ cat /etc/tmpfiles.d/portage.conf
D /var/tmp/portage 0775 portage portage
x /var/tmp/portage

I used ccache before but building in tmpfs is much faster.

I'm currently experimenting with tuning vm.watermark_scaling_factor as the
kernel tends to swap storms with very high desktop latencies during package
builds which consume a lot of tmpfs. This is behavior I'm seeing since
kernel 4.9, worked better before.

As such, I think it makes most sense to put only /var/tmp/portage on tmpfs.
Programs may expect /var/tmp as being non-volatile over reboots.


-- 
Regards,
Kai

Replies to list-only preferred.