Playing with Sandbox can be tricky. The other day my own box (luckily one not FDE’d) started to kernel panic and I’d just activated about 12 sandbox profiles. To fix, I booted to single user mode (Command-S), mounted the drive (using the command mount -uw /). Then I did a find for all *.sb files (assuming you use the sb extension for your sandbox files) touched that day, deactivated them and rebooted. Oddly, still no dice. Did I miss one? Next, just to verify it was a sandbox issue, I went back into single user mode, remounted the volume and used this command to move the Seatbelt kernel extension to…
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NetApp Failovers
Each controller of a NetApp FAS will typically have two network interfaces. Provided I have two storage controllers (and I usually do) I typically prefer to setup a NetApp in an automated failover scenario. A NetApp active/active configuration consists of two storage nodes) whose controllers are connected to each other either directly or through switches. The nodes are connected through a cluster adapter or an NVRAM adapter, which allows one node to serve data to the disks of its failed partner node. Each node continually monitors its partner, mirroring the data for each other’s nonvolatile RAM (NVRAM). Before configuring the filers for an active/active clustered failover, first verify that the…
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VMware for Mobile Devices
I am one of those weird techies that just likes a phone that works. It seems like the more I do to my phone, the less it works. Therefore, I don’t do much to my phone at all any more. I guess VMware is trying to change that. You see, if I had a bunch of Virtual Machines on my phone then I would have infinitely more games to waste time playing while waiting in line at the bank (OK, so who goes to the bank any more – whatever), I would be able to test code and sites from multiple OS’s and I would be able to hack around…
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More on the Nehalem Xserve
I don’t often wax poetically on technical forums (and it’s my first time doing so on macenterprise.org), nor do I actually post any more overall given how persnickety *some* people are about how you go about posting (*some* of which btw is very understandable). But I like the new Xserve, and after seeing a number of posts on a list that were, well, knocking the new Nehalem Xserves, I had to pipe up on the wtf question about the new microprocessor, Nehalem, and why Apple would have chosen a seemingly desktop CPU for its only server product being offered: While it is correct that the i7/microprocessor architecture is going to…
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Windows memory dump files.
One reason not to disable virtual memory on any Windows boxen is that you might need to grab information from a dump file. If a booted OS doesn’t have at least 2MB of virtual memory then no dump file. The default location of memory dump files in Windows XP is %systemroot%/minidump (btw %systemroot% is your Windows install directory). These are created as a result of a blue screen (bsod is not your friend – unless you’re testing a DoS). Since blue screens are typically due to hardware or drivers, and there are often many of each of those, it can help to check out the dump files. If you have…
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The NetApp Halt Command
When shutting down a NetApp Filer, you should use the halt command. The halt command flushes file system updates (eg – flushing memory to disk) out to disks and clears NVRAM, which helps to make sure the system comes back online properly and no data is lost during the process (’cause you know, data loss is kinda’ bad on your storage devices, right). Flags that can be used with the halt command include -d, -t and -f, which sets a dump string (dirty shut down, only use this if a standard shutdown doesn’t work), an interval for the shutdown to occur (in minutes) and prevents other node from taking over…
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Command Line Managed Options in Safari 4
Safari 4 has a predictive search option, as was previously available with various 3rd party apps and with Firefox. This predictive search also has a short list of recently used search strings. When you use the Empty Cache… option it doesn’t clear out the recent searches. Being curious about how to do clear them (without doing a repetitive search through the list with random data) I went hunting. These are stored in RecentSearchStrings in the com.apple.safari domain. To clear them out, simply issue the following command: defaults delete com.apple.safari RecentSearchStrings Now quit Safari and re-open and viola, a fresh, new empty list. Another item that can be managed with the…
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Fibre Channel Switches vs. Hubs
In the FC-AL (Fibre Channel Arbitrated Loop) protocol, when devices enter loops, they send out a Loop Initialization Primitive (LIP) request for an address. All other activity on the loop then comes to a halt as each node reestablishes its connection. Since a hub-based fabric is one large arbitrated loop (which can in many cases similarly be built without the actual hub but with less aggregated speed), it must be entirely rebuilt every time any device is rebooted, added to the loop or removed from it. This causes the potential for processing errors, iNode issues/volume errors and even physical disk failures. A “LIP storm” can also cause multiple devices to…
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Enable Fast User Switching for Windows (Command Line)
Browse to HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWinlogon in the registry and then change the value of the AllowMultipleTSSessions key to REG_DWORD of 1 (or back to 0 to disable). Very similar to how it works in Mac OS X. If you want to script this (eg – for a login script) then you can use the reg command, for example: reg add “hklmSOFTWAREMicrosoftWindows NTCurrentVersionWinlogon /v AllowMultipleTSSessions /t REG_DWORD /d “1” /f
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Reading Address Book from the Command Line
There isn’t an easy-to-use command line interface to the Address Book. You can use AppleScript with it, but not necessarily the command line. This isn’t to say there isn’t an AddressBook framework waiting for someone to use it. Well, Scott Stevenson posted a tool on his blog, Theocacao. This tool is pretty rudimentary but can be useful for a few basic tasks, and provides a nice framework for the development of a larger tool. Basically, abtool has one positional parameter – a search string. Using that it will look for a pattern in the name. It doesn’t search any of the other fields, use wildcards, nor allow for changing of…