Michael Franti & Spearhead = mfsh

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Went to the Michael Franti & Spearhead show in Madison, WI. This was the third or fourth time I’ve seen them and it just keeps getting better. The Australian band Blue King Brown opened for them. Lots of energy there, and you just can’t beat two percussionists, especially one with two cowbells. One classy touch was when each of the Blue King Brown singers soloed the other two would disappear to stop drawing focus away from the other singer. Very considerate. If you aren’t familiar with Michael Franti & Spearhead and like alternative, reggae, hip-hop, or jazz (they’re kinda all over the place, genre-wise) you might listen to or watch some of their stuff. They’re up on iTunes, too. “I …

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That RAM Usage You're Seeing? It's Filesystem Cache.

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The danger of collecting data is that you need to know what you’re looking at before you conclude anything. I say this because every once in a while someone new to system performance statistics starts perusing all the performance graphs we have for our servers. They see a graph like this: and their reaction, seeing all the green “Used Memory” is “OH MY GOD WE ARE OUT OF RAM GET MORE RAM WHY AREN’T YOU DOING ANYTHING YOU SLOVENLY SYSADMINS OMFG WTF BBQ.” My reaction: A) No, you are not out of RAM. Our other monitoring systems tell us when that happens. B) Operating systems know that RAM is way faster than disks, so when an operating system has RAM …

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iPhone Bricks, MacWorld, and Warnings

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So Jonathan Seff over at iPhone Central bricked his unlocked iPhone by updating it. As Jason Snell said in the comments, “We’re Macworld. This is what we do. We’ll buy Jon a new phone if need be — he bricked his phone in the interest of finding out what would happen.” Awesome. People should be thanking MacWorld. A lot. My thoughts: 1) iPhone owners agreed to the rules before getting into this. The rules included using AT&T, among others. 2) Apple has been silent about all the hacking going on. But, when it came to the update they decided to speak out about it. Why? Does this sound like the behavior of a company that wants to crap on its …

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Reliability Isn't As Straightforward As It Seems

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The concept of reliability isn’t nearly as straightforward as it seems. It also depends heavily on what you are protecting yourself against. A good example of this is hard disks. You can protect yourself against a single drive failure by adding another disk and mirroring them. However, in doing this you add a controller that is now a point of failure. You also add another disk that may fail in a way that causes disruptions to both disks (freak the controller out, freak the SCSI bus out, etc.). Is it worth the additional risk? Sure, as long as the controller is way more reliable than the drives. On the other hand, sometimes the best way to make a service reliable …

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planetsysadmin.com

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Are you a sysadmin? You might want to go check out some of the other bloggers out there. A great place to start is over at planetsysadmin.com. That site aggregates a number of blogs, mainly sysadmin stuff, and their blogroll is a bunch of great folks with a lot of great content. I was picked up by them quite a while ago, but I have no idea if I’m still getting rebroadcast there (I understand, in the past I’ve had a lot of random content). Regardless, good stuff, and worth a read. Not saying I agree all the time, but a conversation is boring if you’re always in agreement. 🙂 This post was originally going to be a “hey, read …

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RAID 5 Is A Cruel Mistress

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I’ve long been a fan of RAID 5. Since you only lose one disk worth of space to parity it has been the best way to maximize local disk space. Sure, the performance isn’t the greatest, but I haven’t had applications that taxed the local drives, and the disk space and generically decent performance has been a good trade off. In the last six months, though, I’ve had three machines die from a double drive fault. This is the Achilles Heel of RAID 5. A single drive failure is as much as can be tolerated. In two of those cases the array had a hot spare drive, and the second drive faulted during the process of rebuilding on that drive. …

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iPhone & Airport Express?

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Wouldn’t it be cool if the iPhone could stream to Airport Express base stations? Like the one in my living room, attached to my stereo? Just sayin’, that’s all.

VM Escape & VMware Critical vmkernel Updates

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The 9/21/2007 SANS NewsBites newsletter has some good commentary on the VMware updates that have shipped in the last two months. In short, if you are running any VMware product you need to be at the latest version in order to be secure against potential VM escapes. Normally virtual machines are encapsulated, isolated environments. The operating systems running inside the virtual machine shouldn’t know that they are virtualized, and there should be no way to break out of the virtual machine and alter the parent hypervisor. The process of breaking out and interacting with the hypervisor is called a “VM escape” and it is bad news. If an attacker can gain access to the hypervisor they effectively have unlimited control …

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What is VM Escape?

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What is VM escape? Normally virtual machines are encapsulated, isolated environments. The operating systems running inside the virtual machine shouldn’t know that they are virtualized, and there should be no way to break out of the virtual machine and interact with the parent hypervisor. The process of breaking out and interacting with the hypervisor is called a “VM escape.” Since the hypervisor controls the execution of all of the virtual machines an attacker that can gain access to the hypervisor can then gain control over every other virtual machine running on the host. Because the hypervisor is between the physical hardware and the guest operating system an attacker will then be able to circumvent security controls in place on the …

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Posting To rottenneighbor.com Considered Harmful

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I just read Lifehacker’s coverage of rottenneighbor.com. A few things stand out to me: Anybody can post anything to that site, so it isn’t clear where the problem lies. Is the problem with the neighbor or with the person doing the complaining? Both sides of the story are not represented. Neighbors you don’t get along with might be just fine for someone else. There doesn’t appear to be any way to retract, dispute, or remove data from the system. So if your neighbor moves the record will continue to stick around. Just think of how this works for apartments, too, especially in high-turnover areas like around colleges and universities (such as when the complaint comes from immature, drunken, partying college …

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