Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Issues related to applications and software problems and general support
rbeat
Posts: 12
Joined: 2020/07/13 11:53:49

Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by rbeat » 2020/07/13 12:49:11

Hi,

I'm a Linux user as opposed to being an expert and my Centos 8 laptop has recently stopped booting (it was working fine, if a bit slow to boot, since January, but suddenly failed). It doesn't even boot with a systemrescue USB. So I googled around and got it into emergency mode and did "mount -o remount,rw /" and can now see / with /bin, /lib /etc etc. but there is nothing under /home. What I really want to do is rescue a bit of code I've been working on which is in my user area under /home so this was a bit frustrating.

Doing fdisk -l I can see /dev/sda, /dev/sda1 … 9 with sda8="Linux filesystem" and sda9="Linux LVM". I did "mkdir /mnt/llvm" and then "mount /dev/sda8 /mnt/llvm" but this contained grub2, efi directories and .img files and no /home.

When I tried to mound sda9 e.g. "mount /dev/sda9 /mnt/llvm2" I get a message "unknown filesystem type 'LVM2_member'. Googling around I found some commands to help mount lvm properly but all seem to give me the same error e.g. "lvmdiskscan" and the error is "WARNING: Device /dev/sda not initialized in udev database even after waiting 10000000 microseconds" which is repeated for all /dev entries endlessly.

Googling this I found this RHEL7 bug report:
https://bugzilla.redhat.com/show_bug.cgi?id=1676612

and there are a few others too, but at this point I am completely out of my depth and can't see anything that actually might fix the issue.

Any ideas out there? Thanks in advance.

Regards,
R.

User avatar
TrevorH
Forum Moderator
Posts: 29069
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by TrevorH » 2020/07/13 12:53:56

Boot in rescue mode, run vgchange -ay then lvs and see what LVM LVs are listed. One of those is likely to be your /home filesystem and needs to be mounted. It sounds like your LVM VGs are not activated so the LVs are not seen hence the need to activate the VG with vgchange.
CentOS 6 will die in November 2020 - migrate sooner rather than later!
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 is dead, do not use it.
Full time Geek, part time moderator. Use the FAQ Luke

rbeat
Posts: 12
Joined: 2020/07/13 11:53:49

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by rbeat » 2020/07/13 15:26:38

Many thanks - I'm in emergency mode (is this the same as rescue mode?) and tried vgchange -ay and got the same "not initialized in udev database" warning.

This bug in RHEL7: https://bugzilla.redhat.com/show_bug.cgi?id=1676612 sounds similar and reckons "Downgrading to lvm2-2.02.180-10.el7_6.2.x86_64 resolves the issue". But I've no idea how to do that, if its applicable...

User avatar
TrevorH
Forum Moderator
Posts: 29069
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by TrevorH » 2020/07/13 15:30:27

Is udev running? Are you in a container like that bz?
CentOS 6 will die in November 2020 - migrate sooner rather than later!
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 is dead, do not use it.
Full time Geek, part time moderator. Use the FAQ Luke

rbeat
Posts: 12
Joined: 2020/07/13 11:53:49

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by rbeat » 2020/07/13 15:37:23

Sorry, I'm a real amateur - how do I know if udev is running? I've gone into emergency mode and the only commands that I have done are the mounts...

User avatar
TrevorH
Forum Moderator
Posts: 29069
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by TrevorH » 2020/07/13 15:43:12

Either systemctl status systemd-udevd or ps fax | grep udev should show you some info.
CentOS 6 will die in November 2020 - migrate sooner rather than later!
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 is dead, do not use it.
Full time Geek, part time moderator. Use the FAQ Luke

rbeat
Posts: 12
Joined: 2020/07/13 11:53:49

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by rbeat » 2020/07/13 15:53:21

It appears not, using systemctl is says "Active: inactive (dead) since Mon...."
And then, amongst other stuff "autonegotiation is unset or enabled, the speed and duplex are not writable"
then "Process '/sbin/modprobe -bv gs' failed with exit code 1."

rbeat
Posts: 12
Joined: 2020/07/13 11:53:49

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by rbeat » 2020/07/13 15:54:05

Sorry -bv sg on that last line...!

rbeat
Posts: 12
Joined: 2020/07/13 11:53:49

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by rbeat » 2020/07/13 23:25:31

OK, so I've worked out how to get udev running (useful things READMEs): I did "systemctl start system-udevd.service" and now I see that udev is active and I see a process with the ps.

Unfortunately this hasn't fixed my problem - still the same warning...

Would be grateful for any other ideas/suggestions.

Thanks,
R.

rbeat
Posts: 12
Joined: 2020/07/13 11:53:49

Re: Centos 8 emergency mode "Device /dev/sda not initialized in udev database"

Post by rbeat » 2020/07/14 07:18:35

Actually, getting udev running again does seem to have worked. Reading around, there does seem to be something going wrong, but its just a delay so I left the vgchange running last night and I now have 3 logical volumes in group "cl" active. lvs similarly lists "home", "root" and "swap". Can anyone point me at the command to mount these?

Post Reply

Return to “CentOS 8 - General Support”