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Re: Service names for Debian mirrors in cloud infrastructure



Bastian,

On 25 January 2016 at 12:44, Bastian Blank <waldi@debian.org> wrote:

> This is true for public Azure, however not for others like Azure China.

I have no reason to doubt that things can be a lot different in China,
but this information is not available at the Azure pricing page
mentioned before.

> There is still outgoing traffic (a TCP connection needs data in both
> directions).

Yes, I can't ever disagree with you on this. Let me rephrase it then:
"... The outgoing traffic is negligible."

Doing some tests with an instance on EC2, upgrading it from Jessie to Sid:

"ifconfig" says: "RX bytes:23674 (23.1 KiB)  TX bytes:25207 (24.6
KiB)" after the first SSH login on it after boot. A "sudo apt update
&& sudo apt full-upgrade" states that:

(...)
220 upgraded, 55 newly installed, 4 to remove and 0 not upgraded.
Need to get 151 MB of archives.
(...)

After the upgrade, the output of "ifconfig" has changed, but we have
some data about incoming/outgoing traffic:

(...)
RX packets 118373  bytes 171471859 (163.5 MiB)
(...)
TX packets 15798  bytes 1281682 (1.2 MiB)
(...)

Regarding the ratio of incoming/outgoing bandwidth usage, the later
one represents ~0.73% of the first one. And some part of it was text
that was outputted to stdout/stderr and sent over SSH (using
compression) to my terminal.

Ok, this is not free, but even if you have a cluster of hundreds or
thousands Debian instances on Azure (or any other cloud provider),
this "less than one percent" of "wasted bandwidth" is something that
will be really meaningful on your monthly bill? I do agree that using
the providers' internal mirrors has some advantages, but I'm not
really sure if "outgoing bandwidth costs" is that important to focus
on.

P.s.: we should also note that I was considering an external mirror
all along. What was mentioned before was that we should take in
account even the costs of TCP packets used in a HTTP 302 redirect from
"httpredir.debian.org" to the internal mirror, which is unbelievably
less meaningful. The only use case that I can see that would not be
served by this redirection is if the instance is totally locked from
the internet and only allowed to make requests to the provider's
internal network.

-- 
Tiago "Myhro" Ilieve
Blog: https://blog.myhro.info/
GitHub: https://github.com/myhro
LinkedIn: https://br.linkedin.com/in/myhro
Montes Claros - MG, Brasil


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