On 10/12/14 18:13, Jeff Boyce wrote:
Greetings -
The short story is that got my new install completed with the partitioning I wanted and using software raid, but after a reboot I ended up with a grub prompt, and do not appear to have a grub.cfg file. So here is a little history of how I got here, because I know in order for anyone to help me they would subsequently ask for this information. So this post is a little long, but consider it complete.
Brand new Dell system with two 3GB drives in this system with RAID1 LVM taking all the space outside the boot partitions. I initially created the sda[1,2] and sdb[1,2] partitions via GParted leaving the remaining space unpartitioned. A gpt partition table was put on both drives. During installation Anaconda recognized everything properly which resulted in the following partition summary:
sda1 /boot/efi 500 MB EFI System Partition sda2 /boot 500 MB xfs vg_jab-hostroot / 8 GB LVM xfs RAID1 vg_jab-hostvar /var 4 GB LVM xfs RAID1 vg_jab-hostswap /swap 2 GB LVM swap RAID1
The installer also recognized and listed these unknown partitions that were untouched during installation. sdb1 vfat 500 MB standard partition sdb2 vfat 500 MB standard partition
Installation proceeded successfully, and after the initial reboot of the system I used mdadm commands to watch the raid complete building before doing anything else (I know, not necessary but I am doing other things and had the time to let it complete). I rebooted the system and got a terminal prompt as expected (no GUI installed). At this point I needed to copy my /boot/efi and /boot partitions from sda[1,2] to sdb[1,2] so that the system would boot from either drive, so I issued the following sgdisk commands:
root# sgdisk -R /dev/sdb1 /dev/sda1 root# sgdisk -R /dev/sdb2 /dev/sda2 root# sgdisk -G /dev/sdb1 root# sgdisk -G /dev/sdb2
Results of the first command above: Found invalid GPT and valid MBR; converting MBR to GPT format. Warning the kernel is still using the old partition table. The new table will be used at the next reboot. The operation has completed successfully. The same note (from the Warning on) was repeated for the other three commands.
I then installed GRUB2 on /dev/sdb1 using the following command: root# grub2-install /dev/sdb1 Results: Installing for x86_64-efi platform. Installation finished. No error reported.
The upstream docs (see below) seem to suggest 'grub2-install /dev/sdb' rather than /dev/sdb1 (i.e, installing to the device rather than a partition on the device). I don't know if this is the cause of your issue.
I rebooted the system now, only to be confronted with a GRUB prompt. Thinking that this is a good opportunity to for me to learn to rescue a system since I am going to need to understand how to recover from a disk or raid failure, I started researching and reading. It takes a little bit of work to understand what information is valuable when a lot of it refers to GRUB (not GRUB2) and doesn't make reference to UEFI booting and partitions. I found this Ubuntu wiki as a pretty good source https://help.ubuntu.com/community/Grub2/Troubleshooting#Search_.26_Set
I found the upstream documentation for grub2 to be useful:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/htm...
Included is a procedure for completely reinstalling grub2 which might help you recover.
Below is the current information of my system as seen by grub;
grub# set (the important grub2 variables are:) prefix = (hd1, gpt2)/grub2 root = hd1, gpt2
grub# ls -lha Device proc: filesystem type procfs Device hd0: no known filesystem detected Device hd1: no known filesystem detected Partition hd1, gpt3: no known filesystem detected Partition hd1, gpt2: filesystem xfs Partition hd1, gpt1: filesystem fat Device hd2: no known filesystem detected Partition hd2, gpt3: no known filesystem detected Partition hd2, gpt2: no known filesystem detected Partition hd2, gpt1: no known filesystem detected
grub# ls (hd1, gpt2) -l / /efi /grub /grub2 vmlinuz -3.10.0-123.el7.x86_64 initramfs-3.10.0-123.el7.x86_64.img ... plus some other files
Looking through the directories, I see that there is no grub.cfg file. Other than grub not recognizing the filesystem on hd2, the directories on hd2, gpt[1,2] seem to be identical to hd1, gpt[1,2] as I would assume based on the sgdisk commands I gave to copy them. My initial thinking is that I need to re-run grub2-install on hd1 (sda), but I need a running system to do that. So following the guidance I had I issued the following commands in grub to boot the system.
grub# linux /vmlinuz -3.10.0-123.el7.x86_64 root=/dev/sda2 ro grub# initrd /initramfs-3.10.0-123.el7.x86_64.img grub# boot
Unfortunately the system hung on booting, with the following information in the "journalctl" file: # journalctl Not switching root: /sysroot does not seem to be an OS tree. /etc/os-release is missing. Initrd-switch-root.service: main process exited, code=exited, status=1/FAILURE Failed to start Switch Root. . . . . . Triggering OnFailure= dependencies of initrd-switch-root.service. Starting Emergency Shell. . . Failed to issue method call: Invalid argument
Now I am not sure that I want to get misdirected to what the problem is with this boot, if I can boot from a CD in linux rescue mode and do the grub install, then be back to a booting system. So lets ignore the boot error if we can. So I boot from a CD in rescue mode, and it is only able to automatically mount sd3 under /mnt/sysimage (the LVM RAID1 containing mounts for / and /var). I am able to manually mount sda1 and sda2, but am not sure at what level in the filesystem to mount them (i.e., at /mnt/sda1 or at mnt/sysimage/sda1) in order to properly run grub2-install.
So that is where I am at now. I would like to know how to repair the system, rather than starting over on a new install. Can someone enlighten me on what I need to do from here. Also if someone can speculate on why my grub.cfg is missing in the first place I would be interested.
Also, please cc me directly on any responses, as I am only subscribed to the daily digest. Thanks.
Jeff Boyce Meridian Environmental www.meridianenv.com