A simple matter of…

So, how was Linuxworld? Great!

I went as part of the Opsview team and met lots of potential new customers ranging from very small to very large. Opsview is a monitoring system for networks, servers and applications. Based on Nagios, it’s substantially better.

The conference went very well, we had a modest stand since we aren’t burning through lots of VC cash (yes, that’s a hard-disk rodeo….). Even better we won the Linuxworld excellence award for best system management tool

On Friday I _finally_ picked up my new toy and I’m loving riding it. If only the weather in this country was a little better than it’s been recently.

Leaning into corners rather than just going around them is much more fun, you also feel much more connected with the world. It’s so impractical compared to a car (other than in fuel economy) - you have to suit up, you are exposed to the elements and more importantly the idiots who drive on the road, however it is so much more fun than being in a car

Well I’ve had enough of Xen - I’ve recently moved a disk from hdd to hdc and since I referred to it in a xen domain, when I tried to start that domain, it hung for several minutes (other domains also seemed to stop responding for a while) and then failed with:

abridgett@ripley:/var/log/xen$ Error: Device 2081 (vbd) could not be connected. Hotplug scripts not working.

I checked the config and spotted the problem, but there is no excuse why this is not reported better by Xen. Even in the multitude of Xen logs, only one mentioned it - and that itself shows bad checking!

+ logger -p daemon.debug -- /etc/xen/scripts/vif-bridge: 'Writing backend/vif/7/
0/hotplug-status' 'connected to xenstore.'
+ xenstore-write backend/vif/7/0/hotplug-status connected
stat: cannot stat `/dev/hdd6': No such file or directory

This by itself wouldn’t be enough to drop Xen, but the fact that it’s stuck on 2.6.18 (for Dom0) means that I’m having to backport more and more fixes and I’ve finally had enough. The only reason it’s not been replaced yet is that my hardware doesn’t support KVM (no hardware support on the CPU) but the hardware seems to be becoming unreliable (although it might be bad error recovery on such an old kernel) so I think it is probably time to upgrade anyhow.

At the end of this week I’m off to LinuxWorld Expo in San Francisco.

I’ll be there as we are now partners of Altinity. Altinity make Opsview - which is a customised Nagios. In particular it is much easier to setup and administer - there are many great features including:
* Distributed monitoring with high availability and fail-over
* Much improved SNMP support with trap processing with rules engine
* API supporting automation of Opsview configuration
* Data warehouse for storage of historical performance and event data
* Opsview Reports customisable reporting
* Powerful configuration and management UI
* Extended monitoring UI
* Extensible architecture based on Catalyst Web Framework and Altinity middleware software

It will also be a great opportunity to talk to other companies and perhaps catch up with an old friend.

I was sad to see that Randy Pausch has died. If you’ve not seen it, you really should watch the last lecture. Even if you are (like me) someone who hates “go get them” videos, just bear with this one, even if you think it’s going to get your hackles up, it won’t. It’s because not only does Randy believe, he has done what he says - even to the end.

Occasionally we’ve had this during a tomcat restart at a customer site.

After a little while we rebooted. Next time it occurred on a test platform and I could check shared memory (using ipcs and ipcrm commands), all files (temporary files etc). Then I restorted to “strace” which allowed the app to start.

Next time I was watching top and saw that despite having “-Xmx1536M” it still ate 3GB of memory and then fell over (this is a 32-bit userspace box so that’s the most it can have without horrible performance draining 4+4 kernels). Even -Xmx1300M it still fell over.

Now I was fairly sure it was a race condition or timing issue - and indeed, I now have a nicer workaround than rebooting (which is an admission of failure). The workaround is to drop all the caches so that the box is just as slow as after a reboot:

sync
echo 3 > /proc/sys/vm/drop_caches

We’ll also be upgrading the JVM from 1.5.0-10 to 1.5.0-14 to see if that helps.

pot - “The PM said “unnecessary” purchases were contributing to price rises”.

kettle - “The UK is to slow its adoption of biofuels amid fears they raise food prices and harm the environment”.

As has been known for quite some time that biofuels in their present form are bad:

• heavily subsidised (otherwise they would be incredibly uneconomical)
• generally take more energy to make than they produce (bad for the environment)
• use food crops up hence driving those costs up too
  

Dear government, mandate what should happen, not how to do it. Leave that to the scientists. Well you could except that you:

• ignore them (even when you ask for their recommendation!)
• don’t pay them enough
• seem to pay more attention to clergy on scientific matters
• or tabloids

That’s “passed” with an “a”, not an “i”.

On Thursday I passed by DAS Motorbike test. I’m now able to ride any motorbike I like (after my CBT test last year I could ride anything up to 125cc).

Many, many thanks to Steve and Tim at Bike2Bike for all the training and persevering with me through my U-turns.

The secret to U-turns for me (in addition to looking down the road and _never_ touching that front brake) was firstly to ensure you have a little bite (little bit of revs, little bit of clutch, little bit of back brake) so that you are moving forwards, but the key for me was to turn the handlebars. I don’t mean gradually, I mean going from straight to full lock immediately - I then naturally balanced the bike (generally by leaning in a little and a little power) and took the U-turn okay. You need that full lock immediately as a U-turn in a road isn’t far off the bike’s turning circle.

Now I’m looking at gear and bikes - cheers to Richard and Priscilla for all their advice yesterday. I’m not there yet, but I’ve finally got a decent idea of what I need to look for and good gear that I can buy (I’ll look a bit more first though).

I’ve blogged about last.fm before, but it’s so good it’s worth mentioning again. It’s changed a fair bit since I last used it, the client has got better (it’s also as simple as “apt-get install lastfm” in Ubuntu and Debian for us Linux users).

A recap - you run last.fm, type in an artist you like and it streams music by artists it thinks you might like to you. For free. I really like it and have found several artists from it - in particular there are many I’ve never heard of. One thing I’d like is the ability to listen to a particular artist. You can love/skip/ban tracks.

The client now has information about the artists. I just wish lyrics were there too as I have a (bad) habit of singing along but my memory fails me way too often.

Well it looks like it’s time to plan a replacement server. My trusty Ideq Biostar which I’ve had since 2004/2005 is still fine, however there are some bugs for which I need to upgrade the kernel and it’s stuck at 2.6.18 since Xen hasn’t been ported to a newer kernel. I’ve backported a few fixes, but really it’s getting a drag. Furthermore the fan in the PSU has been dodgy for ages and I’m sure it chews a fair amount of power.

New server will be small and support KVM virtualisation. Current contenders are:

• Atom CPU based machine - 1.6GHz but not that fast
• [Intel Core 2 duo http://www.mini-itx.com/2008/03/06/intels-eaglelake-mini-itx-boards] DQ45EK or DG45FC with E8200 (£90)
  

The Atom is much lower power (4W), but also lower performance - the E8200 is about 40-50% faster than my current E6300 desktop. On PC Mark 2005 we have:

• current desktop: 4794
• E8200: 6833
• Atom230@1.5GHz: 1406
  

I think the Atom may well be too slow unfortunately. It’d be nice to have the laptop T9300/T9500 processor - 2.5/2.6GHz rather than the 2.67GHz of the E8200, but the TDP is 35W rather than 65W (although mostly it’ll be idle). In fact the T8100/T8300 would do nicely - not as quick, but cheaper. As usual wikipedia is the best source of information.

There also seems to be confusion as to which Atom CPUs have VT (virtualisation extensions).

I’ll also need a new case for the current two IDE disks (and no doubt a slimline DVD drive).

Update: Jetway Mini-ITX look tempting too. Case suggstions welcome.