Category: Tech

Even now and then I get bored and look on youtube at the odd video. One thing I notice is that in the comments for a video you have the option of flagging comments as a “poor comment” or a “good comment”. You also have the option of filtering the comments you see to only show those with scores of greater than -10 , -5 , 0 , +5 or +10 ).

The problem appears to be that nobody ever rates comments as good. So this feature is completely useless. To check I had a look at the top 8 videos on the most viewed videos of all time page and even though most of the had thousands of comments not a single comment was rated better than +5 . In other words a complete rating system for video comments that is completely unused by anyone.  Perhaps they should just remove the buttons.

I also noticed that the most viewed video on youtube ever ( Avril Lavigne – Girlfriend ) is “not available in your country” when I try to view it. I assume this says something about somebody’s business model.

At work last week we were looking at backups on a group of machines that had been installed by another company but which our team had recently taken over. I was interested in the backup system they had which involved doing a lvm snapshot of the boot partition and then rsyncing this to another machine is the group ( the rsync’s went around in a circle more or less).

This looked quite cute for quick machine recoveries ( we kickstart our servers but we are still at the stage of doing a fair bit of post install setup ) and we had a think about recovering machines by doing a simple kickstart, then netbooting the server, mounting the root partition under the netboot and rsyncing it back to the install. This seemed a promising idea which we thought would only take an hour or so per machine.

However over the weekend I had a bit of a think and it popped into my head that Mondorescue almost did this sort of thing out of the box already. So I’ve been playing around a it this week with it.

So what I have now ( testing using a scratch VM ) are a few commands that:

1. Backup the server to a NFS partition.
2. Make an differential backup since the previous backup

Which means I now have a directory on a NFS server with a couple of bootable ISOs sitting in it. One has the full backup of the machine ( it’s about a third of the size of the used space ) and the other has any changes made since the first was done. I do the differential since the full backup takes about 30 minutes of hard work for the server while the incremental only takes 3 minutes or so ( YMMV ). I’ll probably do full backups every week and differential backups nightly.

The fun bit is the recovery:

1. Remove console the server and boot it over the network
2. Use PXE to boot the full backup mondorescue image
3. Mondo boots and thee automatic restores the server to the state is was when the last backup was made (about 15 minutes) . I then have to hit enter a couple of times to reboot
4. Netboot the incremental mondo image.
5. Mondo now applies any changes between the last full and the last differential backup.
6. Reboot again to the hard drive
7. Finished, machine should be up and running.

A bit of testing shows this only takes about 20 minutes for my test VM ( 3 Gigabytes of default RHE 5 goodness ) and production servers shouldn’t be much slower ( more data but faster disks and CPUs ).

With a bit of luck I should have this ready to deploy in a few days ( although I’m a little short of NFS space to apply it to every machine ).

Overall a fun couple of days, depending on how it goes I might even do a lightning talk about it at the Sysadmin Miniconf next month although I’m not sure if it’s a little trivial since this is close to “out of the box” functionality for Mondorescue.

I’ve just moved this blog’s software from nanoblogger to wordpress.

Things appear to be mostly working but I’ve got a bit of tweaking to do, plugins to add, tags and categories to create etc. However old article links mostly work.

Also as covered in techcrunch bloglines appears to be having serious problems with at least 10% of feeds completely broken and other unreliable. So if you are using bloglines you probably want to seriously consider moving to google reader or some other alternative.

Recently [Jurgen Appelo](http://nooperation.typepad.com/about.html)
listed the [Top 100 Blogs for Development Managers](http://www.noop.nl/2008/09/top-100-blogs-for-development-managers-q3-2008.html) .

Now the list looks okay except for the first entry – [Joel on Software](http://www.joelonsoftware.com). Now I’ve been subscribing to
the site for a few years along with at least 100,000 other people (
about 10,000 times more than read this blog) but I really question it
being number one anymore.

Sure there are great articles and Joel is a smart guy who creates things
like [Stackoverflow.com](http://stackoverflow.com) but I doing really
think his blog deserves the Number 1 ranking anymore.

The main reason is that Joel doesn’t really write any articles. Looking
at his [archive page](http://www.joelonsoftware.com/Archive.html) we can
see the recent history:

Year	Number of articles

2000	42
2001	23
2002	14
2003	12
2004	9
2005	22
2006	20
2007	12
2008	4 so far

Yes, just 4 articles this year so far and the [last one](http://www.joelonsoftware.com/items/2008/05/01.html) was in May, over
6 months ago.

Now Joel is doing the odd smaller post, he podcasts and writes articles in Inc
but the point of reading the blog is the content there, not somewhere else.

So really, you can’t rate a blog that hasn’t had a real post for 6 months as being
the top blog in the world for software development managers. Even [Paul Graham](http://www.paulgraham.com/) posts more often.
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