On 07/31/2016 08:37 AM, Jörg Schaible wrote:
Hi,
for my backups I use a 3TB USB drive (one big ext4 partition) without any
problems. Just plug in the cable, mount it and perform the backup. The
partition (sdi1) is detected an mountable without any problems:
this tells you the device is valid and working. good.
However, when I boot a rescue system from a USB stick, the partition on the
USB is not detected. I already tried latest SystemRescueCD (default and
alternate kernel), Knoppix and the Gentoo Admin CD. Nothing, the partition
is not available.
So there could be a multitude of reasons. Did thos systems have a bios
that support booting from a usb device? Are the bios setting set to
select the bios device correct?
I recently read somewhere the usb devices only support (2) types of
image booting, but I cannot find that doc right now. rodsbooks is
an excellent resource for all the issues around booting and device
and various hardware/firmware issues. LikeWhoa has made booting the usb
for gentoo, commonplace so search out those postings on the gentoo
forums and in the wiki.
What's the difference? Why does my kernel find this partition and the other
one's do not? It's pretty silly to have a backup drive and cannot access it
in question ;-)
It could be many things. You just have to ferret thru ideas until
something works for your hardware, and it is a frustrating process.
make sure the image you are trying to boot is on a compatible partition
and file system that is supported by the boot image.
hth,
James
