On Aug 21, 2012, at 6:53 AM, Camaleón wrote:
On Mon, 20 Aug 2012 13:37:43 -0700, Weaver wrote:
I regularly log 40-47Kb/s on updates.. Cheers,
And so do we all... The problem here is not the network bandwidth,
it's that some parts of the update process have to download a lot of
small files (a few KiB each). Each file involves a negotiation
process that needs several round-trips and one or more file-directory
lookups on the part of both the server and the client. The round-
trips may be on the order of hundreds of milliseconds, so the time to
retrieve a 4 KiB file can be on the order of a half second or more.
That translates to 8KiB/s for that particular file. Sad, but it's a
fact of life on a global-scale packet switched network.
Look at the reported speed when downloading a large package. Here you
have the opportunity to take full advantage of a big pipe and large
windows on each end to fill the pipe. Your limiting rate here is more
likely to be the ability of the server to get your file off its disk
at the same time as it's getting other files for other clients off the
same disk.
For example, I find that getting security updates is much slower
(factor of 4 or 5, often) than getting new packages from one of the
big mirrors. The "security.debian.org" server seems to be a
bottleneck. There's a design trade-off here -- between getting
security stuff posted and available quickly (in favor of a single
server or at most a small number of servers), and getting it out at
high bandwidth (in favor of mirroring it to lots of servers with the
attendant polling delays) the Debian folks have opted to get security
stuff available quickly but at a lower bandwidth, and regular package
updates available with some delay but at higher bandwidth.
Hope this helps to understand what you're seeing.
Rick
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