[SOLVED] Mysterious 8 second delay in boot after grub

hackerb9 · 09-16-2017, 06:20 AM

Are you still having this problem?

I recently had a similar problem on an Ubuntu machine and it turned out GRUB was taking 2 seconds to load the kernel and 6 seconds load the initial ram disk. You can check if that's the case for you by putting "echo" statements in /boot/grub/grub.cfg before the "linux" and "initrd" commands in your default GRUB menu entry.

echo 'Loading Linux kernel ...'
linux /boot/vmlinuz-4.4.0-93-generic root=UUID=b2e326f9-bf78-46e2-bb27-b0703cd0361e ro
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-4.4.0-93-generic

Note that this isn't a permanent change as the grub.cfg file will be overwritten next time you run update-grub. I don't know how Fedora configures things, but in Debian and Ubuntu you can make those echo statements be added automatically by editing /etc/grub.d/10_linux and changing the variable "quiet_boot" from 1 to 0.

crxssi · 09-16-2017, 08:36 AM

We are not having the problem anymore. One of my staff fixed it and I do not recall what he did and apparently I forgot to come back here and update this thread with the solution. My bad. I believe it was related to grub and/or kernel flags.

toolpost · 09-18-2017, 08:06 AM

Nice to know that you solved the issue. Unfortunately, I am still facing this annoying problem with fully updated fedora 24.
I have inserted the echo statements in grub.cfg as 'hackerb9' suggested. These are my findings.

Quote:

Loading kernel ... (2 seconds)
Loading initial ramdisk... (6 seconds)
Probing...... (Booting starts)

So I am loosing 8 seconds everytime my computer starts. (Apparently I already lost 8 seconds per day for 365 days which is about 48 minutes!.. hahaa..). If you can recall how you corrected this issue, it will be really helpful.

rknichols · 09-18-2017, 08:48 AM

I just fixed a similar problem in a CentOS 6 installation by copying the initrd to a new file and then moving that file back to the original name. I have no idea why the original allocation of the file on the drive was causing GRUB to take a long time to load it, but the problem went away. This was on an SSD, so seeks should not have been an issue, and both files showed a similar pattern of ext4 extents when examined by debugfs. No, S.M.A.R.T. was not reporting any issues on the SSD.

toolpost · 09-18-2017, 05:41 PM

Thanks for your advice, but it doesn't solve my issue. I copied the file to home, deleted the original one, then copied it from home. And similar to your case, this problem started after I installed a new SSD.

This is a snippet of my grub.cfg. Could you find anything suspicious?

Quote:

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Fedora (4.11.12-100.fc24.x86_64) 24 (Workstation Edition)' --class fedora --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-4.8.16-200.fc24.x86_64-advanced-9aa1950b-1716-4243-8397-f8c57071da83' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 --hint='hd0,msdos1' 8eae9d83-a05e-49fc-b739-4d7b6d7e5c20
else
search --no-floppy --fs-uuid --set=root 8eae9d83-a05e-49fc-b739-4d7b6d7e5c20
fi
echo 'Loading Kernel...'
linux16 /vmlinuz-4.11.12-100.fc24.x86_64 root=/dev/mapper/fedora-root00 ro rd.lvm.lv=fedora/root00 rd.lvm.lv=fedora/swap LANG=en_IN.UTF-8
echo 'Loading ramdisk...'
initrd16 /initramfs-4.11.12-100.fc24.x86_64.img
}