zeroxcool.net – Harm van Tilborg

Back again, finally :). First of all (yes, I am 22 days to late): a happy new year dear reader :D.

After a two week break (last week I finished my one and only exam of TLA) I am starting my second internship on monday. I have been at TNO twice by now, discussing some things of the project I am going to work on. And I have to admit, I am really looking forward to start with it.

I also received most of my grades this period. In my previous log you will find some explainations of every course: UID: 8, LOG: 7, ProTes: 6 and ProKwa: sufficient. Up-to-date readers will notice that I haven’t got TLA back, that’s true, that will be in the beginning of February, but I think that’s not going to be a problem. I also finished my ISA course (ISA courses are supposed to give you a roundtrip to other professions, but I followed ‘designing educative websites’, not quite a problem though). I made a website about the WK voetbal 2006 (World Championship Football) this year in Germany. The site is in Dutch and not quite finished, however, it’s a good starting point for everyone who like to know something more about this major event :).

Well, I have to go to bed. Tomorrow a friendly match with the first team, maybe I will catch some minutes of playtime. Next time maybe some more on my new refereeship at the KNVB and some information about the 3Com CoreBuilder 3500 I have bought.

Pfff, finally an update. Have done a lot since last month. Let’s talk about the split of our first e-mail server. That didn’t went very well the first two times (saturday night and firday night). The first time we crossed by that about 15 domains had mailboxes bigger then 1Gb. Imagine that an average e-mail is about 2k, so that there were 1G / 2K = 536.870.912 files into one directory. And that these were also very fragmentated (because mails are not flushed to the disk beyond each other). So transferring of these directories took too much time (about one hour each). So we skipped the whole thing to a week later.

That friday night, with all the courage we had we tried again (in the meantime we had trashed those – big – e-mail boxes). Almost everything went well, only some particular domains didn’t work well. The next day our support box was filled with lots of e-mail about slow POP connections etc. Also our Mail eXchangers (that are the servers in the MX records with SPAM- and virusscanning) were kind of overloaded. After seeking for the problem for almost three days we found it. The harddisk in the new POP-server was really slow (15MB/s at idle) so we had to go another night to replace the new POP-server with a good new server :). This was planned for Saturday afternoon (there was good weather so the server weren’t that busy). But when I finished setting up the new POP server, I got an SMS from my colleague Freek that the ‘real’ POP server was down. I logged in and saw that the filesystem was mounted read-only. Fuck, the harddisk crashed 16 hours too early :).

So, we had to prepare ourselfs for another night datacenter. The harddisk was fully lost so we had to use the backup from Friday morning, so people who didn’t fetched their e-mail this day have lost e-mail received that day. Nothing to do on that. After unpacking the backup we were able to restore the new POP-server (pop03) so that everything worked well. With solving this problem the load of the MXs also lowered. So the slow/damaged harddisk was the originator of this problem :(.

Enough about the Tiscom e-mail system ;). I’m back at school since the 31th of August. I still have to come into the ‘one-hour-rhytm’, but that will happen within two weeks. After that everything must go fast and the next vacation will arrive soon :).

Also football is going fine, I’m playing in our fifth team and sitting on the bench at the first team. Speak you hopefully a bit sooner ;).

Not very much to tell. The POP proxy project is almost finished. All the domain transfer scripts, the domain list transfer scripts etc. etc. are made. But we’re still waiting for the new mailserver, where half of all the domains at the first mailserver will be moved to. But it should be there before saturday. That night we are going to replace everything. Move half of the accounts to the new server, move the servers fysically to a new rack and to install the POP proxy, that is. I’ll share the ‘transfer-domain-to-other-vpopmail-server’ script with you on my qmail page, some days :).

The DigiMatrix project isn’t quite active yet, as I’m working on the e-mail change and Harmbox, an analystic tool I’ve created during my internship at Bronkhorst Travel. That all takes a lot of time. And there’s also the training of my football team. We’ve had about 4 training sessions by now and in one hour the fifth one. My condition was really good, I wasn’t the first one gapping after a run exercise ;). Also goalkeeping went very well, had lots of difficult balls, without even a keeper training session. That’s quite some years ago that happened last :). Well, everybody, have a nice vacation. Till the next log!

Not quite an active log, huh. Time to change, I’m not going to tell you what I’ve done and what I didn’t, just anything I _would_ like to talk about. It was just annoying to tell everything I’ve done this week, so there wasn’t a motivation to log. Well, now there is.

This week I’m having a week of vacation. Well, vacation, let’s say, not going to school. Because I had to do lots of things for school this week. We’re working on a GPS program (on PDA and desktop) to make it possible to set out walkings with a GPS device. Quite interesting project, but it takes lots of time. We’re still running on schedule, I hope in a few weeks I can show the final results.

At work everything is also fine. We’ve introduced – after months of testing – finally our virus- and spamscanning – mail exchangers. Our mail system is now much more reliable to outages of one particulair server. I’ve ASCII-arted an impression of the current situation:

	MX1	= mx1.mail.tiscomhosting.nl
	MX2	= mx2.mail.tiscomhosting.nl
	POP01	= pop01.mail.tiscomhosting.nl

	 /----------------\				/----------------\
========\|      MX1       |				|     POP01      |/==========
inet in	||   virus and    |========\		/=======|  POP archiver  || inet out
========/|  spam scanner  |        |            |	|		 |\==========
	 `----------------'        |            |	`----------------'
				   \[ internal ]/
				   /[ network  ]\
	 /----------------\	   |		|	/----------------\
========\|      MX2       |	   |		|	|     POPxx      |/==========
inet in	||   virus and    |========/		\=======|  POP archiver  || inet out
========/|  spam scanner  |				|		 |\==========
	 `----------------'				`----------------'

As you can see, mail only comes in via the two MX servers. They scan all e-mail on SPAM and virusses. Virus e-mail is immediately deleted, SPAM e-mail otherwise is being tagged with an striking subject name. After that it is forwarded through the internal network to the POP-servers, they store all e-mail for clients and give them out on request. The internal forwarding is done by SMTP and the POP-servers only allow SMTP-traffic from the internal network.

Well, if one of the MX servers is down, there’s no problem, the other one will still receive incoming e-mail. If one of the POP-servers fails, the mail is still being queued at the MX’s. They will deliver everything when the POP-server is comming back up. The only remaining problem, when a POP-server is down, clients are unable to download their e-mail, that shouldn’t be a big problem because the POP-server didn’t have a higher downtime than a half an hour last year. Nice solution we still think.

Tomorrow again a football match.