Using Portage TMPDIR on tmpfs

[JonathanVQP]

I am running Gentoo in Vmware using 16 Gigs of ram. I am trying to increase the emerge process by using ram to emerge. I am using tmpfs. I have read in previous forums that people have put /var/usr/portage in RAM instead of HDD which speeds up the process considerably. However, tmpfs is using volatile memory so when does tmpfs write to disk? When I tried to emerge Gnome on tmpfs, I received the "no space left on device" so I increased the tmpfs space. I am worried that if I place all of /var/usr/portage in Ram using tmpfs, it won't write to disk and loose everything if my vm crashes or power is shut off. I have looked at zram and zswap but what would be the better choice for my situation?

[SlashBeast]

Using tmpfs for portage tmpdir have a drawback of using ram, also, tmpfs can be swapped out.

Keep in mind that some packages will require at minimum 2 GB of ram per one parallel make job, Chromium for example will need more than 2 GB per parallel job, so if you have 16 GB of ram, and build chromium with make -j8, unless you have swap, you will run into OOM Killer.

There's usually hardly a reason to use tmpfs for portage tmpdir unless you have plenty of ram, and even then, it's good idea to exclude some packages, like chromium, from using it, via /etc/portage/package.env.

[NeddySeagoon]

JonathanVQP,

tmpfs does not write to disk.
the content of tmpfs can be moved to swap but thats slow and should be avoided.

tmpfs is implemented using all the same code as any other filesystem, except the disk bit is missing.
From that, it follows that putting /var/tmp/portage into tmpfs actually saves very little time because if you have the RAM to make it work, the kernel virtual memory system is doing it for you anyway.
You save the time for the writes that will never be read. That's only fraction of a second, ever on a big package.

Nothing will be lost, at least no more than normal, if you lose the content of /var/tmp/portage.
Its only used for temporary build time products that will be discarded when the build completes anyway.
The last step in any build is to merge the completed build to the root filesystem.
The root filesystem is not on tmpfs, so the things you want to keep are committed at the end of every package.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[pietinger]

JonathanVQP,

it also depends what you are doing additionally to your emerge. Browsing the internet costs much RAM. I have an Intel I7 with 16 GB RAM and a SSD and using KDE (plasma).

I have in my fstab:

[JonathanVQP]

pietinger: I fully aware how long it takes to emerge QTWebengine since it took 18hours for me. Since you use tmpfs, does it write to disk when it gets full? That is my main concern. Since I have 32 gigs of RAM, RAM is not really a concern. My main concern is making the emerge process faster and if I can use RAM to make it faster and then have it write to disk when it done. When I got the "device is full" error, it appears that it does not write to disk when full.

[NeddySeagoon]

JonathanVQP,

tmpfs can be swapped but if that happens tmpfs should not be used for that package.
Set the build location for PORTAGE_TMPDIR on a per package basis.

Individual builds cannot be continued by emerge once they have been stopped for any reason.
The interrupted package will start from the beginning again.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[AlexJGreen]

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[pietinger]

[Hu]

[pietinger]