Homo-Adminus Blog

This weekend I was doing some development for one of our projects and we needed to make screenshots of a web pages (see my next posts about this task). I’ve managed to develop small piece of code which uses GtkMozEmbed component (Mozilla Gecko-based renderer for web pages) to create screenshots of any page, but there was some problem… The problem was a following: GTK+ library can’t work w/o fully-functional X server running on your machine. Obviously I didn’t want to run such software (no monitor/keyboard/mouse, dumb graphics adapter on the server, etc, etc) so I’ve tried to find some solution… And in this tiny article I’ll describe the method I’ve managed to find.

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This week aside from tons of different tasks I was working on one of MMM users complaint regarding some issues with MMM on Solaris 10. I knew that this OS has not so user (admin) friendly environment (especially for people with strong GNU-related background), but had no other options and decided to install Solaris 10 in VMWare Fusion on my desktop.

Installation was a bit strange comparing to Debian/RHEL/Ubuntu and FreeBSD where I have a strong experience, but I’ve managed to install it successfully. The major problem after my first boot was a lack of knowledge about how things could be done in Solaris… Below I’ll describe what generic Linux admin could do with Solaris to make it easier to use and more friendly for GNU-addicted mind 😉

Notice: If you’re Solaris administrator, please, don’t read further because I’m pretty sure that all these suggestions would look dumb for you (I knew some old solaris admins before and they hated GNU environments).

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Few days ago I worked on some customer’s server and there was a problem – their nfs server went down and we were forced to change some settings on their FC4 clients to prevent shares from dieing because of kernel bug. But when we’ve changed settings in /etc/fstab there was one more step before task was completed – we need to remount this share (I mean unmount/mount). But how to perform this operation if there are some processes in D (non-interruptible sleep) waiting for dead share and prevent it from unmounting? They wait because of hard option on the share and lack of intr option and any unmount request would produce a following results:

So, here is a list of steps you need to do to be able to remount your share.

First of all, you need to send KILL(9) signal to all you processes waiting for share. I’ve used ps axu and filtered all processes in D state. When all processes ‘killed’ (they can’t be killed actually), you’ll need to send the same signal to rpciod processes in your system. After this all your sleeping processes will die and you’ll be able to unmount your share.

That’s it – simple and really useful tip for people using NFS in their systems.

Yes! We did it! Just before I went to bed at 3:40AM (heh 🙂 ), I noticed, that someone submitted new video to BTV. I’ve approved it instantly and then noticed a following information in the top part of the site: “We have 1000 videos / 569+ hours of high-quality content!” So, we broke trough 1k videos barrier! And we’ll try to do 2k videos before the end of this year, we have some new features in closed beta testing which would greatly increase number of submitted videos each day.

Thanks to all our users for their contributions and support! Stay with us and we’ll try to give you more features really soon.

If you’d take a look at any web site, you will notice, that almost all of the pages on this given site are pretty static in their nature. Or course, this site could have some dynamic elements like login field or link in the header, some customized menu elements and some other things… But entire page could be considered static in many cases.

When I started thinking about my sites from this point of view, I understood, how great it would be to be able to cache entire page somewhere (in memcache for example) and be able to send it to the user without any requests to my applications, which are pretty slow (comparing to memcache 😉 ) in content generation. Then I came up with a pretty simple and really powerful idea I’ll describe in this article. An idea of caching entire pages of the site and using my application only to generate small partials of the page. This idea allows me to handle hundreds of queries with one server running pretty slow (yeah! it is slow even after all optimizations on MySQL side and lots of tweaks in site’s code) Ruby on Rails application. Of course, the idea is kind of universal and could be used with any back-end languages, technologies or frameworks because all of them are slower then memcache in content “generation”.

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