[Yum] [UG] parallelizing downloading

[Brian Long]

On Thu, 2005-06-30 at 19:59 -0400, Robert G. Brown wrote:
> Brian Long writes:
> 
> > Even on 100BaseT or Gigabit LANs inside the same DC, parallel downloads
> > reduce the time it takes a sysadmin to patch their linux host.  When we
> 
> Impossible, 

I understand what you're saying and I apologize for the mistake.  The
only time we've seen parallelization improve things is over the WAN.
Because of 65ms latency between RTP, NC and San Jose, CA, we can multi-
stream downloads faster than we can perform a single-stream download.

For example, with our current OC-12, a single host might get 3MB/sec
single stream between the two destinations, but that same host can get
4+MB/sec with 2 streams, 5+MB/sec with 3 streams, etc.

When we had a T3 between RTP and SJ 5 years ago, FTP's throughput was
something like 300KB/sec single stream, but I could get 1-2MB/sec with
multiple streams between the same two hosts.  Altering TCP windows
didn't seem to help (this was on Solaris).

I was incorrect in mentioning the LAN + parallelization.  I meant to
state that over a WAN, it helps extraordinarily.  :-)  Considering we
plan to keep our server farm in SJ and cache the content globally, I
guess parallelization isn't a must.  It would be nice when we have
development hosts in RTP point to our SJ yum repos, though.

/Brian/
-- 
       Brian Long                      |         |           |
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