[Yum] Yum speedup

Jochen Wiedmann jochen.wiedmann at gmail.com
Wed Mar 29 07:02:30 UTC 2006


On 3/29/06, seth vidal <skvidal at linux.duke.edu> wrote:

> wouldn't that mean you'd need a hostname and txt entry for each
> repository on a server?

Even worse, you'd need one for any software package. :-) But that
would not be a problem: The server could serve its replies from a
single large text file, or at least from one text file per repository,
however you like it.

I see other problems, though:

- Software package names aren't made for mapping to DNS names. I'd strongly
  suspect that one would run into problems, sooner or later.
- DNS is quite an unusual technology for these kind of things. While people are
  used to running an HTTP or FTP mirror, it would be quite difficult to convince
  them that they'd need to run a DNS server.
- The length of host names in DNS is restricted to, I believe, 255
characters. (Any-
  one said "C"? :-) I'd expect that such a system would require looong names,
  sooner, or later.
- A single DNS lookup is fast, of course. However, I do not see that a single
  lookup could be sufficient for yum. The typical operations (update
and install)
  require checking of dependencies, aka header files. And these *must not* be
  transferred via a series of UDP packets.

Personally, I'd propose a different approach. While up-to-date
versions do really matter when I am fetching security updates, they
are typically less important when doing an "install". It could be
configurable, how frequently yum updates its cached lists, depending
on the operation. For example, I could configure "every time" for
"update", and "two weeks" for "install".


Jochen

--
Whenever you find yourself on the side of the
majority, it is time to pause and reflect.
(Mark Twain)



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