[ale] GATech mirror problems - from the admin

[James Sumners]

Thank you for the response. I was hoping someone such as yourself
would see the discussion :)

Right now, I'm on campus at Clayton State. So I'm connected through
Peachnet. If I use ncftp to connect to ftp.gtlib.gatech.edu and do a
list, this is what I get:

`Logged in to ftp.gtlib.gatech.edu.
ncftp / > ls
Data connection timed out.
List failed.`

That is with passive mode enabled. As I mentioned in the other thread,
I was able to download a file without using passive mode a couple days
ago. That was a fleeting moment of success, though.

As of right now, I have switched to the Notre Dame mirror for my
Debian machine and the Ibiblio mirror for Arch. Hopefully this
situation with the gtilib server works out soon. I really prefer using
that mirror.

Again, thank  you for the update as well as the service.

On 4/25/07, Neil Bright <neil.bright at oit.gatech.edu> wrote:
> Hi folks,
>
> As the admin of the GT linux mirror, I'd like to comment on some of
> the issues people have been raising.  Hopefully, I can at least
> provide some explanation as to the behaviors people have been seeing.
>
> General FTP problems -
> I'm using vsftpd with PASV enabled (the default behavior).  Please
> ensure that you use ftp clients that understand this portion of the
> protocol.
>
> DNS issues -
> These reports seem to stem from the use of the ftp-
> linux.cc.gatech.edu name.  GTLib is no longer housed within the
> College of Computing, but rather from our central campus IT
> organization - the Office of Information Technology.  The CoC
> maintains their own DNS infrastructure and I can't vouch for it's
> reliability.  The *.gtlib.gatech.edu names use our central campus DNS
> infrastructure.  Another portion of my responsibilities at GT is
> campus hostmaster, so I'm a bit more comfortable making guarantees
> about these names.  If you are having problems with them, please let
> me know.  Output from tools like dig and the contents of resolv.conf
> will be especially useful in these situations.  ;)
>
> General performance problems -
> We've been getting pretty hammered lately...  We're on the Fedora YUM
> lists, we host debian and ubuntu, we're part of rsync.us.gentoo.org,
> we host Suse, Mandrake and Mozilla.  The There's an architecture
> diagram here [1] for those interested.  A couple of the switches have
> been rearranged since I last updated the graphic, but the important
> parts are correct.  Of course, this means that the MRTG graphs are
> incorrect now....  *sigh*  However, there is also a Ganglia instance
> at [2].  In addition to the usual stuff, I also have additional
> gmetrics tracking the number of active apache, vsftpd and rsync
> connections.  There are also some bits in there related to NFS as well.
>
> For the last while, the default 256 connections on all three of the
> apache front end machines have been in use.  Likely, the performance
> issues people have been seeing lately are latency issues while
> waiting to establish a connection.  (At least, this is my current
> theory, feel free to shoot holes.  :)  Many of these connections have
> been coming from the dreaded "download accelerators", often times
> with 20+ connections coming from the same IP address.  I understand
> that NAT on the other end of the pipe will look like this, but I am
> unaware of a programatic way to distinguish between NAT and abuse.
>
> For now I've increased the MaxClients setting, but my current long
> term thinking is to employ some sort of per-address connection
> limiting.  If anybody has suggestions on how to do this I would love
> to hear from you.  I have RHEL4 with the provided apache, vsftpd and
> rsyncd on the hosts.  All four hosts are attached to the same Cisco
> 2970 with a Cisco 6509 (Sup2 & SFM) router running IOS 12.2 and Cisco
> FWSM running 2.3(4) firewall context.  The hosts could be moved to a
> 4948 if that would make a difference.  (Due to topology changes, this
> will likely happen anyway.)  Donations of memory for a SunFire v20z
> would always be appreciated as well.  *grin*
>
>
>
>
>
> [1] - http://www.gtlib.gatech.edu/gtlib.pdf
> [2] - http://www.gtlib.gatech.edu/ganglia
>
> +=======================================================================
> =+
> Neil Bright (neil.bright at oit.gatech.edu)                    (404)
> 385-6954
> OIT - Academic and Research Technologies / Georgia Institute of
> Technology
> 258 Fourth Street, Rich Bldg, Rm 266 / Atlanta, GA  30332-0700
>
>
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>


-- 
James Sumners
http://james.roomfullofmirrors.com/

"All governments suffer a recurring problem: Power attracts
pathological personalities. It is not that power corrupts but that it
is magnetic to the corruptible. Such people have a tendency to become
drunk on violence, a condition to which they are quickly addicted."

Missionaria Protectiva, Text QIV (decto)
CH:D 59