Date: Fri, 20 Jul 2001 13:06:32 -0500 From: Stephen Montgomery-Smith <stephen@math.missouri.edu> To: freebsd-hubs@FreeBSD.ORG Subject: Re: CTM Message-ID: <3B587328.1B6C92C5@math.missouri.edu> References: <Pine.OSF.4.20.0107200700120.17067-100000@azure.dstc.edu.au>
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Dear Jason, I think there are two issues here. First, what is CTM and why do people use it, and secondly, what are the mechanics of creating mirrors. So let me reorder your questions into these two groups. jason andrade wrote: > > hi stephen, > > as a mirror admin, i have to admit, i'm still not clear on what CTM > is and who uses it. since you appear to.. > > o what is it ? CTM is a different way to keep up to date with STABLE or CURRENT or up to date with the ports. What happens is this. Let me illustrate with STABLE. There are a bunch of file with names like this: src-4.0400xEmpty.gz src-4.0402.gz src-4.0403.gz src-4.0404.gz .... Each xEmpty file is a complete snapshot of STABLE. The other files are updates - "deltas" - which modify the previous delta. To keep up to date, first you use ftp download the most recent xEmpty file (they come every 100 deltas), and then the deltas that follow, and use the ctm program to decode these files and create their copy of source. Now you can subscribe to mailing lists like ctm-src-4@freebsd.org. This mailing list will send you new deltas by email as they are created. So once you have got started, you don't need to use ftp (although you may choose to do so). > o why would someone need access to it over the CVSup tree ? If you look in the FreeBSD handbook, it says that CTM is a better method for people with bandwidth problems. However, after asking around, it looks like the another main reason people use it is because they have problems because they operate behind a corperate firewall that does not allow for CVSUP. The advantage of CTM is that it only requires ftp and email. I think that if CTM stopped, then we would lose quite a few corperate users. For some corperate users, it would be impossible for them to get their firewalls to allow CVSUP. The issue is Advocacy. If FreeBSD wants to get inside businesses then a mechanism to get FreeBSD inside businesses is a must. CTM is that mechanism. Without CTM they would not be able to track stable and would not get new releases when they were released into the CVS tree. ------------------------------------------------ Now the mechanics of mirroring. I have to say that I have never managed an anonymous ftp site, and have never been involved in mirroring. If someone could tell me how FreeBSD mirroring works, I would appreciate it. I looked around the FreeBSD website, but I couldn't find the right place that explained how to become a mirror. Someone tells me that ftp-master.freebsd.org should be the main place for mirrors to copy from - is that right? Let me try to answer your specific questions. > o where is the "master" site ? The master site where the CTM's are stored is ns3.saargate.de. > o how much disk space does a full current CTM archive require ? If we keep only one xEmpty for each of the five distribution sets, then it comes to just over half a gigabyte. If we want to have a few months of archive, then maybe 3 or 4 gigabytes. > o how does one mirror it ? rsync ? ns3.saagate.de is anonymous ftp, so I guess that you use one of the ftp mirroring programs. As I understand it, rsync would require giving someone ssh access. I think that this could be arranged if people want to do it this way, but there would be trust issues involved. (But maybe I'm wrong - please correct me of I am.) > o how does one make it available to end users ? (plain old http/ftp?) plain old ftp. > > There is a folder pub/FreeBSD/CTM/x-faulty/ that need not be mirrored. > > Why does this folder exist if it shouldn't be mirrored ? It is now deleted. > > There is another issue. The host computer that creates the CTM delta's > > sends them to ns3.saargate.de, and the copying process can take a long > > time (like 12 hours for files like cvs-cur.7300xEmpty.gz). For this > > reason, there is a big possibility that if you download this file, you > > will only get half of it, because it is still in the process of being > > copied. And you will have taken several hours to do this copy, in the > > process occupying a huge portion of the bandwidth of ns3.saargate.de. I > > guess a few days later when your mirroring software runs again, you will > > see that your copy and ns3.saargate.de's copy are different. Does that > > mean that it will be copied all over again? > > unless locking is implemented, very probably. how large is the file ? what > you've described above doesn't lend itself to mirroring/replication at all > well in its current setup. > The file is about 300 megabytes. I will try to find a way to stop this "half way uploaded" effect from happening. (The way I can think of is to download the file to a different directory, and then use the mv command. Is there a better way?) Tell me what you require, and I will see what we can provide. > -jason > -- Stephen Montgomery-Smith stephen@math.missouri.edu http://www.math.missouri.edu/~stephen To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hubs" in the body of the message
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