Advice on building a CPAN mirror

rah has asked for the wisdom of the Perl Monks concerning the following question:

Greetings,

Can anyone offer any advice, assistance, or even an RTFM about how to create a CPAN mirror? I'm looking for the practical stuff, beyond the FAQs on CPAN itself. My concern was the initial load. That concern turned out to be justified. Using the FTP mirror script pointed to from the CPAN FAQ, I was able to start pulling the archive. However, my FTP sessions would invariably die before a very significant portion was transferred.

Later I tried rsync (which has gotten me into hot water with our security group, who didn't want to open the firewall to a protocol they weren't familiar with). This clearly was a better, more efficient approach. But the initial load is huge. The MOTD displayed on the rsync to the main CPAN archive even warns against trying to pull the entire archive.

My question is; have any brother monks, set up a CPAN mirror, and if so, what advice could they offer on the best approach for the initial load? By author seems to be the primary means by which the archive is organized. Thus far, I have been stepping through subsets of the alphabet, to try and transfer more manageable sized pieces. Is this the best approach? Suggestions?

TIA,
-rah

Comment on Advice on building a CPAN mirror

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•Re: Advice on building a CPAN mirror
by merlyn (Sage) on Jun 28, 2002 at 03:01 UTC

stonehenge.com

And I'd definitely recommend rsync over FTP. Rsync just plain rocks. I'd be happy to talk to your admins to let them know that rsync servers are no less secure than FTP servers.

-- Randal L. Schwartz, Perl hacker

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Re: Advice on building a CPAN mirror
by crazyinsomniac (Prior) on Jun 28, 2002 at 10:17 UTC

The place I mirrored it from is funnet.fi, which most people rsync from (almost all of the active mirrors mirror funnet which is practically always up to date). funnet rocks!!!!!

Visit http://mirror.cpan.org/, and register your mirror with them (or just find the mirror you wish to rsync from).

Just forget about the initial load. It'll take you a about 10 hours or more, depending how many days you stretch it accross (took me about 12 cause I did it over 4 days). This is with a 100MBit connection via funnet.fi.

http://mirror.cpan.org/search.cgi?country=Finland
http://mirror.cpan.org/showmirror.cgi?name=ftp.funet.fi

advice
If you want to set up a private/local mirror of CPAN but do not want to advertise it you do not need to contact the CPAN admistrators. You need to assess which of the public CPAN sites would give the best FTP bandwidth for you (during the nighttime, mind) and then contact the email address dst_contact given in the MIRRORED.BY file to learn the best time of the day to do your mirror. Mirroring software is available from CPAN itself.

ftp://ftp.funet.fi/pub/languages/perl/CPAN/MIRRORED.BY

______crazyinsomniac_____________________________
Of all the things I've lost, I miss my mind the most.
perl -e "$q=$_;map({chr unpack qq;H*;,$_}split(q;;,q*H*));print;$q/$q;"

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Re: Advice on building a CPAN mirror
by ehdonhon (Curate) on Jun 28, 2002 at 13:39 UTC

I actually set up a CPAN mirror earlier this year.

Unless you find that you can get significantly better network performance on a closer mirror, I recommend just going with funet.fi. From what I've gathered in my communications with them, they don't seem to mind, and it really is the most reliable. (You should still ask first). I started with a local mirror, but then switched over to funet whenever that other mirror dropped off the face of the planet without a trace.

As for the MOTD, you need to understand that ftp.funet.fi rsync server is hosting more than just CPAN. That MOTD is saying don't try to download their entire site. If all you are doing is rsync'ing the CPAN repository, that is ok.

I definately suggest rsync over ftp. If your security people don't know what rsync is, work hard to extend them a clue. As of this morning the repository size is 1.2 gigs. My last rsync (running twice a day) used less than 9 megs of traffic and took about 4 minutes for all of CPAN (your speed results will vary depending on your bandwidth).

Other advice:

If you are setting up a cron job to update your mirror, make sure you mail yourself the results so that you can monitor everything. I'm glad I did this or I would have never known that the mirror I was maintaining went stale when the other mirror disappeared.
Make sure when you pubilish the mirror, you make it available in /pub/CPAN and not in your document root. This will make things easier on you later if you ever decide you want to participate in load balancing.
If you have any other questions, feel free to msg me, or email me.. cpan@pair.com. :)

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Re: Advice on building a CPAN mirror
by rah (Monk) on Jun 29, 2002 at 00:28 UTC

I combined the best of most of them and got the job done. I contacted funet.fi (although I only got the auto-reply before I started pulling data). I used rsync and got around my firewall issues by getting around my firewall, plugging my laptop into a switch between our router and our ISP. Sshhhh! Don't tell the security guys.

After a somewhat painful lesson on how rsync works, I got all the data downloaded fairly quickly. (The other lesson I learned is check out your mirror sources closely. The FTP site I had pulled my preliminary load from was stale by 3 weeks!) I did pull the data down gradually, walking through the alphabetical author/id dirs. Then pulling the whole archive to make sure I had everything and all the links were intact. They were, for the most part, 20 minutes and that step was done!

Once I had the archive complete on the laptop, I rsync-ed my linux box to the laptop. Then I set about the task of making it available to my other hosts (that's where i learned what I did wrong with rsync, and had I RTFM more carefully, I should have caught that mistake. Don't forget the trailing slash on the destination directory!) Set up anonymous FTP on the linux box. Changed the default_site in CPAN.pm on my test box. By end of day I was able to use my mirror to upgrade CPAN on my test host. Cool.

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