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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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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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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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AoE (ATA over Ethernet) and iSCSI are the hot new things. Xen is the hot new thing. I like using hot new things as long as they can be made rock solid.

There happens to be a company (Coraid) that makes a turnkey AoE device. Its far cheaper than a true fibre channel SAN or something similar. Perfect for setting up a SAN over Ethernet device that can serve Xen domU filesystems out to “thin” dom0’s on the network.

Well that’s all well and good but you see I’m always looking to save a buck…

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