I have something very strange that occurred. After updating the kernel
on my host CentOS 7 Dell 2950iii I have found that one of my CentOS 7
guest VMs will no longer boot... it just stops at the grub prompt (a
second VM functions just fine). I have no idea why this problem occurred
and have been unable to fix it. On google I have found several
suggestions as to how to repair grub but so far none have worked. What I
have found so far is this:
grub> ls
(hd0) (hd0,msdos2) (hd0,msdos1)
grub> ls -l (hd0,1) (hd0,msdos2) (hd0,msdos1)
Partition hd0,1: Filesystem type xfs, UUID
250008ab-9fde-4892-a8b7-a38882b1a1448 - Partition start at 1024KiB -
Total size
512000Kib
Partition hd0,msdos2: No known filesystem detected -
Partition start at
513024KiB - Total size 12069888KiB
Partition hd0,msdos1: Filesystem type xfs, UUID
250008ab-9fde-4892-a8b7-a38882b1a1448 - Partition start at 1024KiB -
Total size
512000Kib
So it appears that (hd0,1) and (hd0,msdos1) are the same partition
containing the boot directory contents
grub> set root=(hd0,1)
grub> ls -l /
DIR 20151002231139 grub/
DIR 20161013022100 grub2/
10190975 20151219235512 initrd-plymouth.img
40655493 20150403032637
initramfs-0-rescue-6494b5d98adc4f66b0cf4c19a0f6ab66.img
4902656 20150403032703
vmlinuz0-rescue-6494b5d98adc4f66b0cf4c19a0f6ab66
252739 20161010232025 symvers-3.10.0-327.36.2.el7.x86_64.gz
29666884 20161013012551 initramfs-3.10.0-327.36.2.el7.x86_64.img
2965270 20161010231818 System.map-3.10.0-327.36.2.el7.x86_64
126431 20161010231818 config-3.10.0-327.36.2.el7.x86_64
5157936 20161010231819 vmlinuz-3.10.0-327.36.2.el7.x86_64
18119089 20161013022032
initramfs-3.10.0-327.36.2.el7.x86_64kdump.img
Is that (hd0,msdos2) the root partition? If is, has it become corrupted
somehow? Can I get this system to boot somehow so that I might fix the
grub configuration? So far I have tried something along these lines with
out success:
grub> set root=(hd0,msdos2)
grub> linux (hd0,1)/vmlinuz-3.10.0-327.36.2.el7.x86_64 root=(hd0,msdos2)/
grub> initrd initrd-plymouth.img
grub> boot
I just get this error:
[ 2.128131] No filesystem could mount root, tried:
[ 2.129038] Kernel panic - not syncing: VFS: Unable to mount root fs
on unknown-block(1,0)
[ 2.130537] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
3.10.0-327.36.2.el7.x86_64 #1
[ 2.132017] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
{remainder of stack dump}
Does anyone have any ideas as to
1.) How to fix the problem?
2.) Why the problem occurred in the first place?
3.) How to go about debugging the problem?
I would really like to know how this problem could have occurred on the
1 VM but the Host and 2nd Guest are just fine?
Thanks for your help.
--
Paul (ga...@nurdog.com)
Cell: (303)257-5208
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