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Something that just about no one out there seems to be doing (yet) is trying to install Debian directly onto network block devices. The Debian installer doesnt support it (yet), grub doesnt support it (usually), and its just generally not an easy thing to do.

Now, there are quite a few ways around this problem. You can install to a ‘real’ computer and migrate the installation to a network block device. You can use debootstrap in place of the actual Debian installation system. You can use a combination of these two methods, NFS root filesystems, TFTP hacks, etc. All of these solutions are lacking in my opinion. I want to run the ‘real’ debian installer against a network block device and boot my physical hardware using only the built in PXE booting capability of the BIOS.

Taking all these issues as a personal challenge, I’ve outlined below how to go about using the regular old Debian Lenny installer directly against an AoE block device.
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I’ve been battling lately with a lot of problems with cman, part of Red Hat Cluster Suite. Specifically, the fencing tool (fenced) is pretty much junk when you try to start using it with Xen dom0’s. After much searching and gnashing of teeth I happened upon this mailing list post. The promise there is that you could take clvm and compile it against openais and get a cluster aware LVM which doesnt require the rest of Red Hat Cluster Suite (and its crappy documentation, crappy fencing, and general all around crappiness). A little more searching turned up this web site from Olivier Le Cam which pretty much did 90% of the work for me.

After some testing I’m happy to say it appears to work smashingly. What follows is a somewhat more complete version of how to achieve the same results on Debian Lenny. Enjoy :)

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I recently purchased a new Apple Wireless Bluetooth Keyboard for use with MythTV. The choice of input device for MythTV is a very subjective thing to be sure, but I love this device because its as small as it can be without feeling cramped, its thin, light weight, and stylish.

Setting the device up to work with Debian Etch is fairly straightforward once you know what to do

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With the forthcoming release of Debian Lenny it happened to be a good time for me to re-evaluate my decision to use one monster RAID6 device to back all my iSCSI targets. I ran a semi-formal test on different disk configurations for software raid and came up with these results…

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Recently I came upon the need to do all my network routing and firewalling inside a Xen domU. I am not the first to do this but I thought I’d do a little write up on it to help others trying to accomplish the same thing in Debian.

The idea here is to end up with (at least) two VLANs on the network with the dom0 and domU’s being able to choose one or both networks on which to exist. In the case of both, you can set up a handy domU firewall/gateway :)

As you can see from the diagram above, we will end up with three bridges in the dom0 with all the appropriate glue to tie everything together. Best of all, this is all assembled on the fly during bootup.

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This wasnt incredibly difficult to figure out, but if you have a Debian etch system with iscsi-target compiled from source (as I regularly do) getting both open-iscsi and iscsi-target to play nice together takes a small amount of fiddling.

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The next phase of this project is choosing AoE or iSCSI. The debate on the relative merits of each protocol continues to rage on the Internet but in my particular case the criteria are pretty simple; which one performs better without causing excessive system load? Just from reading about the two protocols I am already leaning toward iSCSI for the simple fact that I can use all my TCP/IP management tools (routing, NAT, firewalling, etc.) on every iSCSI device. The only (potential) drawback is CPU load on the involved systems since it has to calculate TCP checksums for all those packets. Yes, there are many, many other advantages of one protocol over the other. No, they don’t matter to me in this scenario :-) So here we go!

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On the plate today is getting ethernet interface bonding working to provide load balancing and failover on the dual onboard gigabit interfaces on our home-built Coraid.

This actually turns out to be much easier than expected…

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Performance and failure testing are next up in building our kickin’ iSCSI/AoE device.

The Debian Etch installer supports building and installing onto software RAID arrays. Because of that…

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Todays adventure with building a SAN on the cheap involves attempting to get hotplug working and changing device mappings.

First of all, hotplug. I have discovered that…

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