Tag Archives: linux

Problem with nvidia raid and grub2

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It’s not the first time I have some trouble to setup grub2 correctly with my nvidia raid system (also called fake-raid) … I did not find exactly why, but for sure i never try to install grub2 correctly from yast or in manual mode.

The first solution to find was : how to boot a fresh installed system when the bootloader has not been configured. The solution is here : http://www.supergrubdisk.org. This tool is really simple and so efficient to boot !  I recommend to have this in your linux emergency kit !

The second solution, once the system has start is to reinstall a bootloader. Here, in fact the solution is easy : destroy this f**** grub2 and replace it by the legacy really good grub ! lol

Then it works … last step to me: understand why gnome is taking so long to start ?!? or the answer is in the question …

I love Linux !

Restoring a grub2 bootloader broken

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After I had to change a hard drive for another my linux Opensuse 12.2 grub bootloader was broken, here are some of the learning of this debugging phase :

– Restore grub to the new disk

– Start kernel manually

– Fix hard drive references

At the end, the process to recreate the bootloader and particularly to recreate the initrd file was broken, and I assume bugged. To really make it works, I had to update the whole Linux and again at the end of the process the booloader based on grub2 was impossible to execute. The solution was to select Grub (version 1) and it worked. I assume it was possible before update the whole distribution to use yast2 booloader and choose grub instead of grub2.

When you get a message like waiting for device … to apear at boot, it may be because of the initrd does not contain the right modules to access the hard drive. It appears when the motherboard has been changed.

This article is mostly notes taken during this debugging phase … so do not consider it as an howto but as a list of command and possible way to debug this kind of issues…

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Activate Masquerading (NAT) on Linux router

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To activate NAT on a Linux Box used as a router, just use the following line :

iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

eth0 is the network interface able to access Internet directly

Then you can list the NAT entry in iptables with the following command

# iptables -t nat -L

You can get more details with:

# iptables -t nat -L -v

The conntrack tool also help to see what happen in the NAT

# conntrack -L --src-nat / --dst-nat