Technology – Page 11

High performance Cacti for large installations

Cacti works fine out of the box for dozens of servers, but when you start to hit the hundreds with tens of thousands of datasources you will start to run into bottlenecks, namely poll cycles exceeding 5 mins and graphs with gaps in them. Sound familair? Then read on. Strangely enough Cacti isn’t optimised for large infrastructures using the default install. You need to make a few tweaks in order to make it perform optimally with hundreds of hosts and thousands of datasources. There are three things you do. Install the Cacti Plugin Architecture, Install Boost, and tune the MySQL […]

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iPhone and iOS 4’s persistent wifi

Updated 19/05/2011 There’s not a lot of information surrounding the new persistent wifi feature in iOS 4 and how it affects iPhones. I did some experimentation and managed to find something which i’d like to share with those who are seeking the same information. First of all on iPod Touches, persistent wifi works as advertised and stays on wether or not the phone is plugged into the charger. This is so it can maintain a constant data connection for Push Notifications and mail checking. Now for iPhones. Prior to iOS 4.3, persistent wifi worked albeit conditionally and under the following

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Recovering from accidental VMFS Datastore deletion

When you forcefully remove a Datastore while ESXi servers are still connected to it, all sorts of weird and wonderful things can happen. We recently had a team member accidentally install ESXi onto a LUN, blowing away the Datastore that was on it. ESXi servers become unstable, the VM’s that were running from the Datastore go into a zombie state where they may respond to pings but are not fully there because they are still running from memory but the disks have been removed from under them. The vCenter server will exhibit high DB load as the ESXi servers try to

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How to cancel your Plesk Billing license

Parallels don’t make it easy for you to cancel your license. Just about every webform will not submit unless you have paid for support. I have managed to successfully cancel my license by going to the following URL and using it. This URL doesn’t not appear anywhere on the Parallels site. I can’t remember where I found it but it works. https://www.parallels.com/support/pleskbillingkey

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30fps vs 60fps in games

30 frames per second vs 60 frames per second. Whats the big deal! The human eye can only see 24 – 30 fps right? I’m sure we’ve all heard that argument before. While it’s true the human eye can only see around 24 – 30 fps, in real life we have Motion Blur. Put your fingers up in front of you and wave it around, you’ll see motion blur in action. On screen, this is not the case. Because of the lack of motion blur, on screen objects just don’t seem to move smoothly and appears to skip to the

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