Week 4+ – Beagleboard RAID sever is working.

As it turned out, one of the error types I was seeing was of no consequence.  The mtdblock2 errors are only seen at system initialization when Linux is probing devices. During bootup, it queries the block devices to determine if they contain valid file systems. The NAND block device (mtdblock2) gives errors on the read. This is because the TI omap processor boots from the NAND and uses HW ECC during its boot sequence so the memory is written using HW ECC. When Linux accesses it, it is using SW ECC and the reads generate errors. So the probe of the NAND device gives errors, which can be safely ignored because there is no file system on it anyway.

I was able to get a 3.2.3 kernel running and the root file system is on the SD card (mmc block device). I installed the mdadm package and moved the RAID 1 USB disks. The RAID volume was recognized and I was able to mount it without issue. I configured my new server on my home network as an NFS mount so I can reach it from my other system. I also set up port mapping on my DSL modem to provide ssh access from the internet.

Now I have a RAID server running at under 10 watts. Awesome.

Here it is. It’s a bit cumbersome because the beagleboard doesn’t have on-board ethernet and it only has one USB port. It gets its 5v from the powered usb hub and the ethernet is on usb as well (black thing sticking up from the USB hub). The 2 disk drives (green) are 120GB WD passport drives that I’ve had for a while. The other connector is a serial port in case I have problems that preclude me from getting to it from the network.


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