Arch Linux

sorkaud

Member

Registered: 2015-07-15

Posts: 37

Unable to find root device '/dev/sda2'.

hello

Recently i update system(i think including kernel) and then reboot the system. But the following message comes out and i can't type anything with keyboard.

:: running early hook [udev]
Warning: /lib/moudles/4.8.8-2-ARCH/modules.devname not found - ignoring
starting version 228
:: running hook [udev]
:: Trigering uevents...
Waiting 10 seconds for device /dev/sda2 ...
ERROR: devince '/dev/sda2' not found. Skipping fsck.
ERROR: unable to find root device '/dev/sda2'.
You are being dropped to a recovery shell
     Type 'exit' to try and continue booting
sh: can't access tty; job control turned off
[rootfs /]#

I searched this problem and I found two or more solutions ( one with device name the other with mkinicpio?) and i wanted to test those solutions

But i am really newbie, i don't understand how to start. I can't even type anything

I insert the usb which i use to install arch ,but pc doesn't recognize it. 

how can i start with? (many solutions assume that i can chroot(?) which i can't and i don't understand) Help me plz

lasombra

Member

From: Luzern

Registered: 2011-09-01

Posts: 68

Re: Unable to find root device '/dev/sda2'.

What is the output of fdisk -l ?
What bootloader are you using?

WorMzy

Forum Moderator

From: Scotland

Registered: 2010-06-16

Posts: 11,896

Website

Re: Unable to find root device '/dev/sda2'.

It looks like you have somehow ended up with a kernel and initrd mismatch; your kernel appears to be 4.8.8-2, but your initrd doesn't contain the modules for that kernel. I can only assume that the post transaction hook provided to run mkinitcpio when the kernel is updated on your system, didn't run. Unfortunately the only thing I can suggest is to boot a liveCD, chroot in, and run mkinitcpio manually. Once you have a working system again, you will need to investigate why the hook didn't run (if this is the cause).

---

Sakura:-
Mobo: MSI MAG X570S TORPEDO MAX // Processor: AMD Ryzen 9 5950X @4.9GHz // GFX: AMD Radeon RX 5700 XT // RAM: 32GB (4x 8GB) Corsair DDR4 (@ 3000MHz) // Storage: 1x 3TB HDD, 6x 1TB SSD, 2x 120GB SSD, 1x 275GB M2 SSD

Making lemonade from lemons since 2015.

sorkaud

Member

Registered: 2015-07-15

Posts: 37

Re: Unable to find root device '/dev/sda2'.

thanks for the quick answer. I manage to boot from live usb and i have root@archiso now 

I read about mkinitcpio but i'm not sure how to do

So, i mount my /dev/sda2 (which is / directory for me) to /mnt   mount my /dev/sda1(which i think /boot since it is 512M) to /mnt/boot  and arch-chroot /mnt  ( then root@archiso~# changes to sh-4.4#)

then mkinitcpio -p linux.

Is the above method is safe and right?

I'm sorry i can't copy my lsblk or fdisk -l since i can't run startx (for iasombra)

+ For those who have the same problem.
https://bbs.archlinux.org/viewtopic.php … 0#p1106210
http://superuser.com/questions/769047/u … ux-install    <---  I followed hook part also but i'm not sure that does help me

Last edited by sorkaud (2016-11-22 13:47:55)

WorMzy

Forum Moderator

From: Scotland

Registered: 2010-06-16

Posts: 11,896

Website

Re: Unable to find root device '/dev/sda2'.

You should confirm that sda1 is actually your boot partition before running mkinitcpio, but yes, that is the correct method.

I'm sorry i can't copy my lsblk or fdisk -l since i can't run startx (for iasombra)

If you still need to, you can use a pastebin client for that: https://wiki.archlinux.org/index.php/Li … in_clients

---

Sakura:-
Mobo: MSI MAG X570S TORPEDO MAX // Processor: AMD Ryzen 9 5950X @4.9GHz // GFX: AMD Radeon RX 5700 XT // RAM: 32GB (4x 8GB) Corsair DDR4 (@ 3000MHz) // Storage: 1x 3TB HDD, 6x 1TB SSD, 2x 120GB SSD, 1x 275GB M2 SSD

Making lemonade from lemons since 2015.

sorkaud

Member

Registered: 2015-07-15

Posts: 37

Re: Unable to find root device '/dev/sda2'.

Thanks for iasombra & WorMzy

I did what i write down above and mkinitcpio -p linux make system back (although i didn't know what i did and that it is minimal action - mount root & boot neccesary?..)

So now, how can i chase the reason why update is fail?

Anyway, i think it is a huge update for me because i boot into startx then there is no background image i set up and the font is changed (more thick?) I have to adventure hard my pc for a moment (to find there are more problems , i hope not)

Now i just turned off my pc (for tomorrow)

I will change this topic as SOLVED.

I hope this will help for another newbie.

thanks.

sorkaud

Member

Registered: 2015-07-15

Posts: 37

Re: Unable to find root device '/dev/sda2'.

To WorMzy, It is lucky that my /dev/sda1 is /boot 

and I'm wondering 'what happen if it is another partition like / or /home or /swap?'  (So that mkinitcpio is something changes the file in /boot. Am i right? i guess mkinitcipio deals with booting manual A for computer. My pc do what manual A said to do but while updating, the Manual A didn't changed because mkinitcipo doesn't work. And so i have to do it maually by live usb booting. Am i right?)

Do you have any idea?

Anyway, Thanks very much

(another question : So for preventing these phenomenom, after update - kernel or linux? - , will type mkinitcipio -p linux in the terminal work? (before rebooting)

Last edited by sorkaud (2016-11-22 13:29:03)

mrunion

Member

From: Jonesborough, TN

Registered: 2007-01-26

Posts: 1,938

Website

Re: Unable to find root device '/dev/sda2'.

It sounds like you do not have /boot mounted when you installed the Kernel update. Read the Wiki CAREFULLY on EFI setup and make sure you have /boot mounted (the proper one) before updating the Kernel. Search the forums, there are plenty of threads on that.

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Matt

"It is very difficult to educate the educated."