Hello!
A recent article[1] on Fedora Magazine mentions the fastestmirror and deltarpm options for DNF. They seem quite handy, but are disabled by default. Why is that, and are there reasons why I would not want to have them enabled?
[1] https://fedoramagazine.org/things-to-do-after-installing-fedora-34-workstati...
Hi,
Matti Pulkkinen wrote:
A recent article[1] on Fedora Magazine mentions the fastestmirror and deltarpm options for DNF. They seem quite handy, but are disabled by default. Why is that, and are there reasons why I would not want to have them enabled?
The deltarpm option is enabled by default. But there are issues which prevent it from being very useful unless you are constantly updating (in which case, you're likely not someone who wants deltarpm enabled in the first place).
Here's the documentation from dnf.conf(1) for deltarpm:
deltarpm boolean
When enabled, DNF will save bandwidth by downloading much smaller delta RPM files, rebuilding them to RPM locally. However, this is quite CPU and I/O intensive. Default is True.
It's worth keeping in mind the note that it's CPU and I/O intensive. If you have sufficient bandwidth it's often faster to download the full rpms than to download the delta rpms and re-assemble the full rpms (when delta rpms are being properly generated by Fedora, that is).
Regarding fastestmirror, the first thing to determine is whether or not you benefit from changing the default. You can certainly enable each of them and test -- there's always a strong case to be made for empirical data. :)
Reading the descriptions of each option in dnf.conf(1) provides some hints about why they are not enabled by default.
fastestmirror boolean
If enabled a metric is used to find the fastest available mirror. This overrides the order provided by the mirrorlist/metalink file itself. This file is often dynamically generated by the server to provide the best download speeds and enabling fastestmirror overrides this. The default is False.
As noted, the list returned by the mirrorlist/metalink may already provide a better order than the fastestmirror option will achieve.
[1] https://fedoramagazine.org/things-to-do-after-installing-fedora-34-workstati...
ke, 2021-07-07 kello 17:19 -0400, Todd Zullinger kirjoitti:
Hi,
The deltarpm option is enabled by default. But there are issues which prevent it from being very useful unless you are constantly updating (in which case, you're likely not someone who wants deltarpm enabled in the first place).
Ah, I see. I assumed it was disabled by default because of the article.
As noted, the list returned by the mirrorlist/metalink may already provide a better order than the fastestmirror option will achieve.
Okay, good to know. Thank you.
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Matti Pulkkinen -
Todd Zullinger -
Tom Horsley