Older blog entries for prla (starting at number 124)

12 Oct 2006 (updated 12 Oct 2006 at 10:33 UTC) »
Linux on the HP DL380 G4 and MSA1000

Lately, in what should be my part-time occupation for the next few months, I’ve been setting up a couple of HP Proliant DL380 G4 servers in addition to an HP MSA1000 fibre channel disk array. The idea in this case is to have both servers (henceforth the DL380s) working independently while sharing the storage space provided on the disk array (henceforth the MSA1000) and hopefully having some sort of load balancing going on between the two. Despite some limited experience using and configuring Linux systems in the past few years, this comes as a new and refreshing challenge for me, considering these are enterprise class servers, something I’ve never had a change to directly deploy from the ground up and maintain.

DL380 G4s and the MSA1000 The next few posts are then intended to provide a first hand account of the path I’ll be walking during the setup of these systems, which will hopefully be useful both for me later on and whoever comes stumbling across this page looking for information on how to setup these or similar systems. Compiling a new kernel In order to better understand and get acquainted with the servers, I’ve decided to go for a test run with a Debian-based Linux distribution, called Alinex, which is developed here at the University of Evora. Later on, when most configuration stages are figured out, this will become a regular Debian installation instead of this slightly different flavour. Because the kernel that ships with Alinex is not SMP-enabled, a new kernel is needed to take advantage of the two Intel Xeon 3.8Ghz processors inside each server. There’s also the need to support the fibre channel adaptar, as well as the Gigabit Ethernet adapters, etc. Fortunately, most distros attempt to have as many kernel options set for compilation as modules, so using the distro’s .config file is a good idea. Later on, the goal will be to have a thin all statically compiled kernel. The only exceptions, then, were support for the fibre channel driver and SMP. The former must have generic FC support enabled under Network Device Support and the qla2xxx driver should be configured to compile as a module (it didn’t seem to work built into the kernel, as it wouldn’t recognize the firmware upon boot) under SCSI Device Support and SCSI low-level drivers. This driver needs to have the firmware image placed in /usr/lib/hotplug/firmware so it gets found and used by the adapter at boot time. This image - and others for similar qlogic adapters - can be found at: ftp://ftp.qlogic.com/outgoing/linux/firmware In this case, the correct firmware image for the qla2312 adaptar is ql2300_fw.bin. This information can be found in the help page of the driver in the kernel configuration:

21xx              ql2100_fw.bin 
22xx              ql2200_fw.bin
2300, 2312, 6312  ql2300_fw.bin 
2322, 6322        ql2322_fw.bin
24xx              ql2400_fw.bin 

Configuring the MSA1000 disk array Once the DL380s are up and running, attention turns to the MSA1000 disk array which needs to be setup. To do that, the easiest way seems to be using the old-fashioned serial port access method to connect to the MSA1000 command line interface (CLI) facility. In this case, HP provides a serial to ethernet RJ45Z cable, which can seem weird at first because it won’t fit in a regular ethernet port. This should be connected to the front of the MSA1000 controller while the serial should obviously be connected to the host. Here, I’ll be using the DL380 itself to configure the disk array. Communication can be achieved with any terminal emulator, for instance Hyper Terminal under Windows or minicom under Linux. Both have worked for me, although minicom has a minor quirk in the default configuration which kept me from accessing the CLI at all. Also, instead of the usual 9600 baud rate, this one runs at 19200. So, minicom should be configured using the following parameters:

Serial Device: /dev/ttyS0 (or whatever the serial port used happens to be)
Bps/Part/Bits: 19200 8N1
Hardware Flow Control: No (important! default is Yes)
Software Flow Control: No

Also, the kernel needs to support the serial port in order to do this. Once minicom is set up in this way, hitting Enter after it opens will drop you the CLI shell:

CLI>

The CLI has extensive help facilities so every possible command has a verbose explanation of its doing by simply using the help command. There’s also extensive documentation from HP on the MSA1000, in particular the HP StorageWorks 1000/1500 Modular Smart Array Command Line Interface User Guide

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Catch Up

It’s been a while (again) since my last post so I guess some catching up is in order.

First and foremost, these increasingly longer absences keep me thinking about closing down this place. I had a rationale posted on the first day for why I wanted to have such a blog and for a time it worked out. Right now, despite a lot of things going on in my life, I hardly have anything important to share with my meager audience. I’ve always believed that a non-existent blog is a better thing in the so-called “cyberspace” than one where its author has nothing important to say, so don’t be surprised (not that you would, right?) if this one ceases to exist shortly. Not much entropy getting lost, I guess.

Anyway, the web app I’ve been somewhat talking about for the past few months is still under development. Needless to say, not nearly enough time has been spent on it, at least not as much as I would have liked to give to it and definitely not as much as it needs. Still, it’s usable, it’s real, it already has the potential of making people’s lives (a bit) easier. That’s more than many can claim.

However, we still need to take than final step, which is obviously pushing it out the door, for the world at large to pick it up at will. That’s what we’ve been reluctantly focusing on lately. We started using 37Signals excellent project management web app Basecamp. To quote Jim Coudal during his keynote talk on the latest SXSW, Basecamp (and the other 37signals) take the bullshit out of communication. We’ve been experiencing this first-hand, as Basecamp truly takes a uniquely simplified view of project management and developer collaboration. Everything revolves around three simple concepts: messages, TODOs and milestones. Everything else is just treading water, really, so forget about functional specifications, Gantt charts and all that mess. My chances of becoming a 37signals Getting Real evangelist have just increased tenfold.

We’ve also been using Campfire for real-time chat and that’s been working out too. It’s going to become important from this week on as we will be physically distant for a good three months and the project cannot stop now, of all times. Coupled with Writeboard, Campfire has everything we need to communicate effectively during project development.

So where do we stand right now? As I said before, we’re pushing for public release soon. We’ve set a July 21st deadline ourselves within Basecamp and I wonder how realistic that can be. We’ll try but considering how novice we both are, I seriously doubt it. We already cut a lot of features we’d like to have up front, but there’s a need to realise that “release early, release often” must leap from theory into practice. It was true for open source apps but I believe it’s more true than ever when it comes to web apps nowadays.

Personally, after a long and crappy semester at university, there’s no need or reason to deny that I’m very tired, kind of burnt out actually, and in need of something completely different from what I’ve been doing for the past few months/years. Hopefully next year will be my last academic year (well, it must, as I’ve been doing this for far too long) and then I can look forward to the rest of my life from a very different angle. I don’t want to make these last five or six years sound like crap, because they weren’t, but I guess it’s finally taking its toll. I’ve never been an easily likable person, I’ve always hated going with the flow and making peace both with God and Devil at the same time. But lately it’s been a downward spiral of small, mundane, average, day-to-day conflicts with people that probably don’t deserve it and, most of all, conflicts inside my head. I’m just dog tired of it all and for every place where my guilt is written, here’s an apology.

Well, I guess this is just the net result of these past few months of controlled insanity, of constant restarts. That’s it. Tired of constantly restarting every damned day.

There’s two exams to go and then I can forget about school for a while, hopefully (and that’s a long shot, for a thousand other reasons I could get into but won’t) recharging my batteries for the last decisive year.

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World Cup Calendar

Not that I’m overly excited about the World Cup that is upon us - quite the contrary, actually - but while I was browsing through my feeds I caught myself wondering about the calendar and the schedule set for each match. Couple of seconds later and I arrive at one of Cameron Moll's links, which is none other than an iCal remote calendar with the complete schedule (also available for other applications from that link).

Calendar sharing sure is a sweet thing.

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11 Jun 2006 (updated 11 Jun 2006 at 11:57 UTC) »
Benign FUD?

<wiki> Jason Fried from 37Signals has written a very interesting point of view on how Google may be deceiving the competition by making them look the other way:

What if Google was so brilliantly twisted that theyâ€[TM]re using Writely and Spreadsheet and Calendar and massive numbers of new hires as flares to distract Microsoft (and others)? Shoot up a flare (Spreadsheet) and scare Microsoft into paying even more attention to new attacks from new directions. The flares serve one purpose: to redirect competitorsâ€[TM] energy away from focusing on search/ads, which are Googleâ€[TM]s core competency (and primary revenue source). Hey look over here!!! Is Google the best slight of hand magician around? Is the â€oeGoogle Office†just a head fake?

There may be more to it than meets the eye, but this certainly is true to some extent. I’ve never thought about it this way, though. Again, go Jason.

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Going Mobile

While developing our web app, which we hope to unveil this summer, we felt from the very beginning that we needed to reach out to mobile device users. So after a few months of hammering away at our web version, we feel it’s time to start working on the mobile side of things.

Taking advantage of some theoretical work for a university subject on user interfaces, I was able to gather some knowledge about the current state of the so-called mobile web. And from what I learnt, for us it pretty much boils down to picking one of two options, which are a) a mobile version of the website, which would be accessible through a URL using the device browser of choice or b) a stand-alone application, such as a Java MIDlet.

Both have pros and cons but we decided to stick with the latter. The support for handheld CSS seems to be crafty these days and I guess we’ve already had too much headaches with regular web browsers to plunge into building a mobile web site. Moreover, our conceptual model for the mobile app fits rather more naturally in a stand-alone app, basically because one of our primary goals is to depend a bare minimum on network connectivity. We want data to be synchronized with our server on demand and only then do we need the link. So, forcing our users to rely on network access to even use the app in the first place seems wasteful and uncalled for, no matter how coverage has been and will be improving over the next couple of years.

We still need to cover a lot of theoretical ground before we’re able to even think of pulling this off successfully - for instance, we’re pretty much clueless about SymbianOS support. But for now, I think we’ve laid the conceptual foundation of an interesting side kick for our web app which may - or may not - tell how successful it can ultimately be.

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Slashdot Revamped

Since I can remember, Slashdot always had its same old look. It’s not bad and it’s certainly a trademark. But, in a sense, I believe it also made it look a little deprecated. Now, with the ferocious competition from Digg, Reddit and friends, I guess CmdrTaco and his gang finally decided to do away with the ancient design. So they held a contest for it, offering a laptop along the way.

Personally, I think that instead of hiring some design firm (which could undoubtedly come up with some awesome modern design), it was clever of them to ask the community to redesign the site for them, effortlessly picking the best of the bunch.

Turns out the best is an awesome face lift, which preserves every bit of the so-called trademark, but lends it a totally refreshed and slick look at the same time. The best of both worlds, I say. This is a perfect example of how small (but deep) changes can make a world of a difference when it comes to designing for the web.

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Wordpress Tinkering Reloaded

Hacked away some more on Wordpress this evening and I think this is as far as I’ll go for the time being, considering I’ve finished implementing what I’ve always wanted to have in the first place.

Building upon last night’s modification, I’ve now extended the DokuWiki parser in a way that it picks up the titles of existing pages (listed on the sidebar) and links appropriately back to them, in effect allowing me not to bother with explicit linking. So, say, if I have a page about Apple, which I actually do, everytime I mention it, it’ll get automagically linked to my own personal page about it. Like it just did.

The hack was unreasonably simple and that’s a testament, again, to DokuWiki’s awesome codebase, its parser being particularly well laid out. All I had to do was write the following almost trivial function and call it in the right place inside parser():

function wp_pages(&$table,&$text) {
  extract($GLOBALS);
    
  $pages = $wpdb->get_results("SELECT id,post_title FROM $wpdb->posts " . 
			       "WHERE post_status = 'static'");

foreach($pages as $page) firstpass($table,$text,'/('.$page->post_title.')/s', "<a href="?page_id=".$page->id."">1</a>"); }

All we do is retrieve all page titles from the database and swap their occurrences in the text with their respective HTML links, using DokuWiki’s own firstpass(), which does exactly that. So far I tried to break it in many ways but to no avail, which is a good thing.

Enough Wordpress/DokuWiki hacking now, let’s move on to other things :)

I’ve also added a couple more pages (you can access any of them from the sidebar on the right) and images illustrating a few of them (take for example the Ruby on Rails or Photography pages). Now that I got the basic infrastructure laid out for easily adding structured content to the site, expect an increase in the number of pages in the near future. Hopefully something will also be of interest to you and not just to me.

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Wordpress 2

Spent some time this morning looking into the new major version of Wordpress and despite not having upgraded this very blog into it (yet), I think it’s a pretty decent overhaul. Perhaps not as ground-shattering as you’ve probably have to come to expect from a software’s new major version, but still very much worth to upgrade. I understand from the website that upgrading from version 1 to this one shouldn’t be much of a problem, but still I haven’t tried it yet.

What I did do was giving a shot to the Mac provided Apache server (1.3.33) and installing a fresh copy of WP2 in my iBook’s localhost. The first (and pretty much only) problem I bumped into was that PHP was non-existent, so I just grabbed this nice Apple Developer HOWTO and installation was a breeze. I did notice however that compiling stuff from source with gcc in Darwin is a bit slow, at least on my system.

Once I got WP up and running, I did a quick survey of the administration interface, so here’s some thoughts on it:

  • The admin interface got a face lift, not much a departure but it’s now more blue and generally pleasant to the eye.
  • There’s Javascript goodness all round, the kind that is actually useful and doesn’t get in the way. And it’s cute to boot.
  • The themes section is better presented and there’s now support to edit the Kubrick’s theme header colors from within the admin interface. Only changing the title and description font colors did work, though, which is OK by me considering I prefer to use background pictures in it. But changing the text color easily still comes in handy. This is all part of the Current Theme Options feature, which I assume are different for each installed theme.
  • Of special interest to me and Tiago is the fact that his DokuWiki markup plugin works like a charm under WP2. All it took was simply copying the doku/ folder from my current WP1 installation to WP2’s plugins folder, et voila.
  • RSS feeds seem to be working fine despite Russell's reports on the contrary. I do wonder why Safari’s RSS icon in the address bar looks for the Atom feed instead of the RSS2 one I provide in the links within the blog itself.
  • There’s now a nice feature of importing posts and comments from other blog systems (namely Blogger, Movable Type, TextPattern and plain RSS) into WP2. This is good because now I can actually import all those dozens of entries I got in my old Blogger blog.

And that’s pretty much what I could gather. When I have more time, I will make a complete backup of my current WP installation and proceed to upgrade it to version 2.

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Delusional

Cringely:

The classic example is Microsoft, where hiring smart people fresh from school and working them 60 hours or more per week – in an environment where they don’t even leave the building to eat – leads to a state of corporate delusion, where lying and cheating suddenly begin to make sense.

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Wanna write a device driver for Linux?

I was just lazily going through my feeds and bumped into this. According to KernelTrap, there is now a “Linux Device Driver Kit”. Cool!

The better way to introduce is letting Greg Kroah-Hartmann, Linux kernel hacker extraordinaire, do it for me:

“It is a cd image that contains everything that a Linux device driver author would need in order to create Linux drivers, including a full copy of the O’Reilly book, ‘Linux Device Drivers, third edition’ and pre-built copies of all of the in-kernel docbook documentation for easy browsing. It even has a copy of the Linux source code that you can directly build external kernel modules against.”

This really goes a long way to lower the barrier to entry for wannabe Linux device driver writers. I used to be quite into OS stuff some years ago and for whatever reasons that’s no longer the case, but this is a really nice thing and hopefully it will further enhance Linux kernel development.

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