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The mysterious 8MB block device on Linux

If you ever notice a device like that on your Linux system:

# fdisk -l
Disk /dev/sda: 8 MB, 8388608 bytes
8 heads, 32 sectors/track, 64 cylinders
Units = cylinders of 256 * 512 = 131072 bytes

Disk /dev/sda doesn't contain a valid partition table

… then the scsi_debug kernel driver is present. To get rid of the device either unload the driver or (if e.g. statically compiled into the kernel) use sysfs, like:

# echo -1 > /sys/bus/pseudo/drivers/scsi_debug/add_host

Further details available at

One Response to “The mysterious 8MB block device on Linux”

  1. Matt Simmons Says:

    Interesting! I haven’t had this happen, but now if I do, I’ll remember this entry and come back for the fix. thanks!