microsoft

How to Disable Windows IPv6 Temporary Addresses

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The default Microsoft Windows IPv6 implementation has privacy extensions enabled, where IPv6 temporary addresses are used for client activities. The idea is that IPv6 has so many addresses available to it that we can create extra ones to help mask our activities. In practice these temporary addresses are largely pointless, and are very unhelpful if firewalls and ACLs are configured to allow access from a specific static address. By themselves, IP addresses aren’t a good way to authenticate people but they often form another layer of defense. This is especially important for IT infrastructure where there often aren’t (or can’t be) sophisticated authentication mechanisms. Paste these commands into an administrator-level PowerShell or Command Prompt and then restart your PC: netsh interface …

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Should We Panic About the KPTI/KAISER Intel CPU Design Flaw?

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As a followup to yesterday’s post, I’ve been asked: should we panic about the KPTI/KAISER/F*CKWIT Intel CPU design flaw? My answer was: it depends on a lot of unknowns. There are NDAs around a lot of the fixes so it’s hard to know the scope and effect. We also don’t know how much this will affect particular workloads. The folks over at Sophos have a nice writeup today about the actual problem (link below) but in short, the fix will reduce the effectiveness of the CPU’s speculative execution and on-die caches, forcing it to go out to main memory more. Main memory (what we call RAM) is 20x slower than the CPU’s L2 cache (look below for a good link showing …

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Intel CPU Design Flaw, Performance Degradation, Security Updates

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I was just taking a break and reading some tech news and I saw a wonderfully detailed post from El Reg (link below) about an Intel CPU design flaw and impending crisis-level security updates to fix it. As if that wasn’t bad enough, the fix for the problem is estimated to decrease performance by 5% to 30%, with older systems being the hardest hit. Welcome to 2018, folks. In short, an Intel CPU tries to keep itself busy by speculating about what it’s going to need to work on next. On Intel CPUs (but not AMD) this speculative execution doesn’t properly respect the security boundaries between the OS kernel and userspace applications, so you can trick an Intel processor into letting …

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Disk Partition Alignment Is Still Important

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This is post #9 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” I have written about this almost yearly (beginning all the way back in 2006), but even now I routinely run across something, like a virtual appliance, that has poor partition alignment. What’s the big deal? In short, misaligned I/O is killing your disk performance. Blame Logical Block Addressing, or LBA. Back in the day, a BIOS interacted with drives by knowing the exact geometry of the drive, namely how many cylinders, heads, and sectors were on a disk (CHS). Unfortunately that limited the size of the drives that could be used, and ignored some basic …

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For The Best Performance Use a Recent Operating System and a Recent Hypervisor

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This is post #1 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” Just like in construction, performance tuning is most effective when you have a good foundation. If the underpinnings of your efforts are weak you won’t be able to build a skyscraper, just a small office building. While that’s still better than nothing, there is often a lot to be gained by using the newest versions of your OS & hypervisor of choice. Some quick examples: Windows Server 2012 R2 added Virtual Receive-side Scaling, which allows the load from network traffic to be processed by multiple virtual CPUs. VMware vSphere 5.5 added support for latency-sensitive VMs, …

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Three Reasons Why Hatred of the Windows 8 UI is a Good Thing

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There seems to be a lot of negative sentiment about the Windows 8 user interface (the interface formerly known as Metro). It might be counterintuitive but I think this is ultimately a good thing. First, mainstream OS user interfaces have stagnated, and I like that Microsoft is thinking about what the next steps might be. I also like that they’re thinking about it in a different way than other OS vendors, especially not emulating Mac OS’ ridiculous skeuomorphism. Trying to maintain some common interface elements between desktops, laptops, and mobile devices seems like a good idea, too. They’re obviously not done thinking about the problem, otherwise they wouldn’t have left the desktop in Windows 8. That’s the main problem people …

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Impressions of Windows 8

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I’ve spent about 20 hours now with Microsoft Windows 8 release running in VMware Workstation 9. I’d looked at the developer preview months ago but not exercised it very much, figuring things would change. Some things did, for the better, but the UI changes, by far the most controversial, stayed pretty much the same. Windows 7 was called the successor to the wildly popular Windows XP but in my mind Windows 8 only succeeds the star-crossed Vista. It’s really too bad that all the seriously cool things — the new task manager, Storage Spaces, all the personalization updates, File History, the task bar improvements, several billion other tweaks — are all being overshadowed by the interface. Desktop PCs are not tablets. …

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Align Your Partitions

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This is post #1 in my December-long series on Linux VM performance tuning, Tuningmas. I wrote about it back in 2006, and lots of others have written about it since (Duncan Epping has a nice vendor-agnostic post with diagrams): misaligned storage trashing your I/O performance. What’s the big deal? In short, it is killing your I/O performance. Logical Block Addressing on your disk drive makes the Master Boot Record 63 bytes long. This means it occupies sectors 0-62 on disk, and the first partition will start at sector 63. The number 63 is a persona non grata in the computer world. It isn’t a power of 2, and it certainly doesn’t line up with your storage’s idea of the world …

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Thoughts on the VMTN Subscription Idea

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Mike Laverick has started something of a campaign to bring back the VMTN Subscription, which was something like the Microsoft TechNet or MSDN models. I’m a TechNet subscriber and for $349 I get access to most everything Microsoft has. For testing purposes this is great. I don’t have to spend a lot of time dealing with activation timeouts, I can just test things and leave the my own test environment up and running for when I want to test new VMware Tools, or whatever. I think that’s fair, since I buy real Windows licenses for every other VM that I have (dev, test, QA, production, etc.). Right now, if you want a test environment your options are to pay for …

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How to Install Microsoft SQL Server 2008 R2 for VMware vCenter 5

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My venerable post on installing MS SQL Server 2008 for vCenter 4 was getting old, so I thought I’d update it, if only because I have a new admin helping me and I’m going to stick him with doing a bunch of installs. Ha! I thank the VMware folks who have incorporated a lot of the tweaks from my original document into the defaults for vCenter 5. They were probably obvious, and not taken from my work, but it’s content I don’t need anymore. Awesome. While I don’t mean this page to become a general support site for vCenter SQL Server installations please leave a comment if something needs to be clarified or corrected, or if I’m doing something dumb …

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