Archive for June, 2014

Code Spaces break-in lessons: using your infrastructure provider for backup is a single point of failure

Monday, June 30th, 2014

Summary of the events of the Code Space break-in: Code Spaces was hosting their services on Amazon Web Services VPS infrastructure. An attacker managed to gain access to their AWS administration console account and after his demands for ransom were not answered, proceeded to delete all the data in the account.

The disaster recovery plan for Code Spaces was based on having machine images and data backups stored in AWS, everything was gone, and Code Spaces basically had to shutdown.

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Why I hate 4K displays

Wednesday, June 18th, 2014

Well, I don’t have very high resolution displays at all (you might call them UHD displays?), but the name “4K” is really stupid – so please stop using it.

What is it 4000 of anyway? Can anyone tell me? Hint – no it doesn’t have 4000 pixels, nor 4000 scan lines or 4000 anything or event anything else that is divisible by 4000. Although the horizontal resolution is almost 4000 (actuallly 3840 pixels wide), and while Wikipedia will have you believe that is the reason for the name, it is not so.

No, the reason is so much stupider than that: the name “4K” is because “4K displays” are 4 times larger (in pixel count) than 1080p displays (1080 being about 1K). This is so stupid, because while UHD displays do indeed have 4 times the pixels of a 1080p (“1K”) display, the 1080 in the number does not relate to the number of pixels – it is the number of scan lines in the picture – of which a UHD display has only twice as much. But “2K” just doesn’t have the right ring to it… so, the branding masters made do with what they have. Sooooo stupid…

What to do when your virtual private server is really slow

Sunday, June 8th, 2014

Ok, this is not a real solution for all types of problems – just a tip, that worked for me today, to try out if you can’t figure out what the problem is.

I’m running a VM on Amazon EC2, and looking at top, I saw that most of the CPU time was spent either in “steal/guest” or “IRQ“. Now steal/guest is kernel speak for “I wanted to allocate some CPU time for progams, but the hypervisor stole it” – which is not surprising on a a virtualization solution, but if it happens all the time then that means that your physical host is constantly loaded by other VMs that take as much CPU time as they can. The second item “IRQ” is time the kernel spends at handling interrupt requests from the hardware. This shouldn’t consume a significant amount of time unless the hardware has a problem – another good indication that you want to move your VPS to another physical host.

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