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Memory issues finally solved
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Loading ...As I posted before in ‘Mysterious problems with my VPS’, I recently got an increasingly unstable VPS system hosting a lot of my and my customers sites. After a lot of digging I initially presumed that Dovecot (the mail server) was responsible for the issues, as you can read in ‘Dovecot causing memory issues’.
Last week I did a lot of debugging on the Debian server to try and find out what was the issue. And initially it was Dovecots memory usage. After disabling this tool for a couple of days the server was still running fine. However the day after I posted the article on Dovecot the server crashed again. So I had to restart my investigation.
First off I had to had to get a better memory management tool, so I installed Htop on the server (apt-get htop). This shows the current memory usage of each running application. After installing this I enabled all services and applications again and started running stress tests. And though Dovecot was causing some peeks in memory usage it did not keep the high memory usage after the requests where done.
As it turns out for some reason Apache 2.2 was using a lot of memory during peak loads. But even more frustrating it didn’t seem to release any memory any more. Which was causing issues for services that only spawn when they are being accessed like Dovecot and Postfix, which explained why both of these services crashed when the server halted.
After tweaking the maximum amount of servers Apache is allowed to start and the maximum amount of client threads to handle the memory usage dropped dramatically. And I am very happy to report that the server has been running again for more then a week, without any glitches.
Still it doesn’t explain why all of this only happened after updating my server with the latest versions and patches. But I’m glad it’s solved for now.
Dovecot causing memory issues?
In my previous post I mentioned that I had and still am having some serious issues with the stability of the VPS I’m running all of my websites on. Though I’m still a long way away from solving the issue, I have figured out that it is very likely caused by an upgrade of Dovecot.
Why I believe that dovecot is slowely over time eating up memory, well after I disabled it the VPS continued running without any issues. I already knew Apache 2, subversion and MySQL weren’t causing it. So I only had postfix and dovecot left to test.
What is truly amazing is that the website for Dovecot indicates it is low in memory consumption, hence it has no settings to limit the amount of memory allocated for Dovecot. So I still need to figure that part out, or alternatively change to a different IMAP server.
Mysterious problems with my VPS
I’ve heard a lot of people always say that you can’t crash/hang or break linux easily. Well then I guess I’m one of the lucky bastards that gets it done. Since a few days the VPS system I’m operating keeps hanging itself up.
Now off course it is not the fault of Linux 
, but with my very lacking skill. I recently did an apt-get upgrade command on the VPS. To my suprise it started updating with Lenny packages, whilst I could have sworn I have Etch installed. Mystery on its own, but worse yet the server now keeps hanging and breaking.
I figured it was a memory issue at first cause some weird service was installed that was eating it alive. So I de-installed that and it ran fine for a few days. But allas, after 3 days of running the VPS hangs itself up again. When I say hangs-up I mean that I cannot connect using SSH, the mailserver goes down. MySQL and Apache keep running though, as does postfix. So I’m still guessing it is memory, but I have no idea why my configuration is no longer working after running an apt-get upgrade command. Something is really wrong 
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First Look On Windows 7
I recently had the option to test Windows 7 the Release Candidate. So I thought it would be good to write a short post on my first thoughts on this latest version of Windows. Don’t expect a lengthy review in this article, I may write on later on though.
After downloading and burning the image I got from Microsoft I quickly tried to install it on my HP TouchSmart PC. Why did I choose this computer rather then my laptop or mediacenter. Well I was honestly expecting a lot of trouble and my TouchSmart has a recovery disk to quickly revert to Windows Vista .
First look at the Windows 7
The installation of windows was damn easy, I guess when you compare the installation it is very similar to Windows Vista. A graphical interface is loaded that will help you trough the various steps needed to install Windows 7. So far so good, though it does take quite long to install. But then again who is expecting anything else from a bloated OS, which I still believe Windows is. After the installation most things on my computer are recognized and work fine. Why I say most things, well unfortunately none of the special buttons of my computer are working. So I can’t control the sound, media or the brightness of the screen. Which sucks, but then again I don’t think I can blame Microsoft for that. As HP does not have any support what so ever for Windows 7.
One cool thing I really liked is that after installing a multi touch driver my HP was able to recognize 2 pressure points on the screen at the same time. Which makes for some cool features that work. I really liked it, but keep in mind it is just some eye candy and won’t help you in the every day things you do on the computer 
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Some new neat features
Some might have already heard about some of the new features included in Windows 7. Well I will try and summarize a few that I find useful and some of which I have serious doubts that they are any added value what so ever.
More decent window grouping
Anyone who has used Windows XP or Vista knows about the feature that windows starts grouping similar windows when there are a lot of them open. Well in windows 7 this feature got extended. Now it groups the windows no matter how many are open. This on its own is not that bad. Because like in Windows Vista you get a small preview of the window when you hover over it. A new feature in this is that when you stay over a window for a longer period of time the window will be displayed on the screen and all other windows ‘disappear’ to the background.
Though this is a pretty stable and nice feature I strongly dislike Windows for doing this same thing for every single tab in Internet Explorer. Which is pretty annoying to people like me who have several tabs open, as well as several instances of Internet Explorer. This causes it to become a bit crowded down in that small preview window.
Better quicklaunch features
One of the older features in windows is the quicklaunch bar in the taskbar. This allows you to quickly start up any program you pinned to it. Well Windows 7 is no stranger to this. It features this prominently and slightly changed. The icons are a lot bigger then before, and like before you can pin any application to the taskbar. One new thing is that if you click on an icon and drag up a quicklaunch window appears with the most used actions, or in case of the explorer the most opened folders.
Speed compared to Vista
A lot of people are comparing Windows 7 with Vista, which I guess is not that strange since they look very similar. One huge improvement is that Windows 7 appears to be a bit quicker and slimmer then Vista. I have not done extensive tests speed wise, but it looks like it boots up a bit quicker and closes quicker. As well as loading of applications this also appears to be slightly faster.
The eye-candy included in Windows 7 is a bit sluggish tough. It’s just that bit lagging behind on commands giving. Like dragging of applications seems to bit just a bit slow. It might have todo with my HP TouchSmart, but Vista runs on it beautifully so I would expect Windows 7 to do the same.
Some related video’s
Like all of you I like vid’s, so I added some nice reviews and feature video’s below. Enjoy them and until next time…
No HDCP using the Gigabyte MA69GM-S2H onboard card??
Ok I recently got a very weird problem with my HTPC. Since a couple of days I’ve been unable to play any Blu-Ray disc. Even after updating my PowerDVD to the latest patched version.
Before this update of PowerDVD the weird behaviour was the disapearing of PowerDVD when playing discs. No message no error nothing, just gone! After the update the DVD player informed me that HDCP was not available and it could not play protected Blu-Ray discs.
This sounded weirdt to me since I have played them in the past, and I know the onboard graphics chip (the Ati Radeon X1250) supports it.
As it turns out, after a lot of digging, I had recently installed an updated version of the Catalyst Control Center. Which should not be anything strange, its recommended practice by a lot of software developers. However the graphics chipset on the motherboard appears to have some custom stuff, since after installing the latest version from the Ati site HDCP was no longer supported.
When I reinstalled the version of the Catalyst Control Center that came with the PC all my troubles went away. No more warnings / crashes or unable to play disc reports.
