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/html/System_Administrators_Guide/ch-Working_with_the_GRUB_2_Boot_Loader.html 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