Grub rescue | error: checksum verification failed.

M

mathd8406

New Member
Mar 24, 2019
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Hello,

I have been installing Proxmox for a week, after restarting Proxmox it remains stuck on the grub at startup, see screenshot added.

====================================================================
Error message : "error: checksum verification failed.
Entering recue mode ...
grub rescue > "
====================================================================

For information my hdd configuration is as follows : zfs (raidz -1).

Do you have any idea.

Thank you for your help.
 

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Hi,

what FS do you use as rootfs.
What have you changed/done?
 
Hello Wolfgang,

I'm not sure I understand the question.
I use as FS zfs.
What is rootfs? how to obtain this information?
No significant changes, just a reboot.

Thanks you for your help.

Sincerely,
 
I had the same problem on two hosts lately.

grub rescue with debug=zfs and ls (hd0,gpt2) shows fletcher4 checksum errors.

I solved this by doing this from the proxmox installer (start installer in debug mode -> CTRL+D -> Accept License Agreement -> Abort):

zpool import -N -R /mnt rpool
zfs snapshot rpool/ROOT@move
zfs snapshot rpool/ROOT/pve-1@move
zfs create rpool/move
zfs rename rpool/ROOT rpool/move/ROOT
zfs send -v -R rpool/move/ROOT@move|zfs receive rpool/ROOT
zfs set canmount=off rpool/move/ROOT/pve-1
zpool export rpool

Just rebooted and all was fine again.

I have however no idea what causes the problem in the first place. A scrub doesn't find any invalid checksums. Only thing both hosts have in common is that they have been installed in december 2018 and january 2019. And yes - both are really cheap systems (Intel Atom, non ECC ram (though a 24h memtest ran without errors)). Both system where frozen and booted directly into grub rescue after being reset.

I hope this small solution helps everybody who runs into this problem.

Best regards
Manfred
 
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Manfred Heubach said:
I had the same problem on two hosts lately.

grub rescue with debug=zfs and ls (hd0,gpt2) shows fletcher4 checksum errors.

I solved this by doing this from the proxmox installer (start installer in debug mode -> CTRL+D -> Accept License Agreement -> Abort):

zpool import -N -R /mnt rpool
zfs snapshot rpool/ROOT@move
zfs snapshot rpool/ROOT/pve-1@move
zfs create rpool/move
zfs rename rpool/ROOT rpool/move/ROOT
zfs send -v -R rpool/move/ROOT@move|zfs receive rpool/ROOT
zfs set canmount=off rpool/move/ROOT/pve-1
zpool export rpool

Just rebooted and all was fine again.

I have however no idea what causes the problem in the first place. A scrub doesn't find any invalid checksums. Only thing both hosts have in common is that they have been installed in december 2018 and january 2019. And yes - both are really cheap systems (Intel Atom, non ECC ram (though a 24h memtest ran without errors)). Both system where frozen and booted directly into grub rescue after being reset.

I hope this small solution helps everybody who runs into this problem.

Best regards
Manfred
Click to expand...

Hi, same issue with one HP DL360e installed in the same period.
Your procedure save my install and lot of time.
Rgds
 
Manfred Heubach said:
I had the same problem on two hosts lately.

grub rescue with debug=zfs and ls (hd0,gpt2) shows fletcher4 checksum errors.

I solved this by doing this from the proxmox installer (start installer in debug mode -> CTRL+D -> Accept License Agreement -> Abort):

zpool import -N -R /mnt rpool
zfs snapshot rpool/ROOT@move
zfs snapshot rpool/ROOT/pve-1@move
zfs create rpool/move
zfs rename rpool/ROOT rpool/move/ROOT
zfs send -v -R rpool/move/ROOT@move|zfs receive rpool/ROOT
zfs set canmount=off rpool/move/ROOT/pve-1
zpool export rpool

Just rebooted and all was fine again.

I have however no idea what causes the problem in the first place. A scrub doesn't find any invalid checksums. Only thing both hosts have in common is that they have been installed in december 2018 and january 2019. And yes - both are really cheap systems (Intel Atom, non ECC ram (though a 24h memtest ran without errors)). Both system where frozen and booted directly into grub rescue after being reset.

I hope this small solution helps everybody who runs into this problem.

Best regards
Manfred
Click to expand...

Hi! Thanks Manfred! Came accross this grub_rescue/fletcher4 boot issue on an old HP G8 and, while unable to access the pool from a proxmox installer console (complained about missing devices, damaged pool... not just one or two, but all the disks!) I was able to follow your steps booting a debian live cd.

Had previously attempted many other ways of getting the thing to boot; as it seemed to be a grub issue, but apparently not... very grateful to you for your post!

Just in case it's useful to anyone, my setup was a standard debian stretch install, with 4 x 3TB drives in two striped mirrors, zfs root, later turned into proxmox. Worked perfectly for some 6 months until a maintenance reboot...

Cheers!
 
Manfred Heubach said:
I had the same problem on two hosts lately.

grub rescue with debug=zfs and ls (hd0,gpt2) shows fletcher4 checksum errors.

I solved this by doing this from the proxmox installer (start installer in debug mode -> CTRL+D -> Accept License Agreement -> Abort):

zpool import -N -R /mnt rpool
zfs snapshot rpool/ROOT@move
zfs snapshot rpool/ROOT/pve-1@move
zfs create rpool/move
zfs rename rpool/ROOT rpool/move/ROOT
zfs send -v -R rpool/move/ROOT@move|zfs receive rpool/ROOT
zfs set canmount=off rpool/move/ROOT/pve-1
zpool export rpool

Just rebooted and all was fine again.

I have however no idea what causes the problem in the first place. A scrub doesn't find any invalid checksums. Only thing both hosts have in common is that they have been installed in december 2018 and january 2019. And yes - both are really cheap systems (Intel Atom, non ECC ram (though a 24h memtest ran without errors)). Both system where frozen and booted directly into grub rescue after being reset.

I hope this small solution helps everybody who runs into this problem.

Best regards
Manfred
Click to expand...
I can see everyone is saying it is possible to tshoot zfs with Proxmox ISO debugging mode, when I booted from it, it says zpool command not found
 
Manfred Heubach said:
I had the same problem on two hosts lately.

grub rescue with debug=zfs and ls (hd0,gpt2) shows fletcher4 checksum errors.

I solved this by doing this from the proxmox installer (start installer in debug mode -> CTRL+D -> Accept License Agreement -> Abort):

zpool import -N -R /mnt rpool
zfs snapshot rpool/ROOT@move
zfs snapshot rpool/ROOT/pve-1@move
zfs create rpool/move
zfs rename rpool/ROOT rpool/move/ROOT
zfs send -v -R rpool/move/ROOT@move|zfs receive rpool/ROOT
zfs set canmount=off rpool/move/ROOT/pve-1
zpool export rpool

Just rebooted and all was fine again.

I have however no idea what causes the problem in the first place. A scrub doesn't find any invalid checksums. Only thing both hosts have in common is that they have been installed in december 2018 and january 2019. And yes - both are really cheap systems (Intel Atom, non ECC ram (though a 24h memtest ran without errors)). Both system where frozen and booted directly into grub rescue after being reset.

I hope this small solution helps everybody who runs into this problem.

Best regards
Manfred
Click to expand...
Will this still work with the rpool/data being untouched? ie no snapshot?
 
Manfred Heubach said:
I had the same problem on two hosts lately.

grub rescue with debug=zfs and ls (hd0,gpt2) shows fletcher4 checksum errors.

I solved this by doing this from the proxmox installer (start installer in debug mode -> CTRL+D -> Accept License Agreement -> Abort):

zpool import -N -R /mnt rpool
zfs snapshot rpool/ROOT@move
zfs snapshot rpool/ROOT/pve-1@move
zfs create rpool/move
zfs rename rpool/ROOT rpool/move/ROOT
zfs send -v -R rpool/move/ROOT@move|zfs receive rpool/ROOT
zfs set canmount=off rpool/move/ROOT/pve-1
zpool export rpool

Just rebooted and all was fine again.

I have however no idea what causes the problem in the first place. A scrub doesn't find any invalid checksums. Only thing both hosts have in common is that they have been installed in december 2018 and january 2019. And yes - both are really cheap systems (Intel Atom, non ECC ram (though a 24h memtest ran without errors)). Both system where frozen and booted directly into grub rescue after being reset.

I hope this small solution helps everybody who runs into this problem.

Best regards
Manfred
Click to expand...

The following procedure allowed me to boot but the next zfs upgrade will break grub again and you will need to do it all again
 
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