9.3. Problems After Installation
9.3.1. Are You Unable to Boot With Your RAID Card?
grub>
) and a flashing cursor might be all that appears. If this is the case, you must repartition your system and move your /boot
partition and the boot loader outside the RAID array. The /boot
partition and the boot loader must be on the same drive.
9.3.2. Trouble With the Graphical Boot Sequence
Procedure 9.4. Disabling Graphical Boot Temporarily
- Start your computer and wait until the boot loader menu appears. If you set your boot loader timeout period to 0, hold down the Esc key to access it.
- When the boot loader menu appears, use your cursor keys to highlight the entry you want to boot and press the e key to edit this entry's options.
- In the list of options, find the kernel line - that is, the line beginning with the keyword
linux
(or, in some cases,linux16
orlinuxefi
). On this line, locate therhgb
option and delete it. The option might not be immediately visible; use the cursor keys to scroll up and down. - Press F10 or Ctrl+X to boot your system with the edited options.
Procedure 9.5. Disabling Graphical Boot Permanently
- Log in to the
root
account using thesu -
command:$
su -
- Use the grubby tool to find the default GRUB2 kernel:
#
grubby --default-kernel
/boot/vmlinuz-3.10.0-229.4.2.el7.x86_64 - Use the grubby tool to remove the
rhgb
boot option from the default kernel, identified in the last step, in your GRUB2 configuration. For example:#
grubby --remove-args="rhgb" --update-kernel /boot/vmlinuz-3.10.0-229.4.2.el7.x86_64
--remove-args="rhgb"
parameter with the --args="rhgb"
paramter. This will restore the rhgb
boot option to the default kernel in your GRUB2 configuration.
9.3.3. Booting into a Graphical Environment
startx
command. Note, however, that this is just a one-time fix and does not change the log in process for future log ins.
graphical.target
. When you are finished, reboot the computer. You will presented with a graphical login prompt after the system restarts.
Procedure 9.6. Setting Graphical Login as Default
- Open a shell prompt. If you are in your user account, become root by typing the
su -
command. - Change the default target to
graphical.target
. To do this, execute the following command:#
systemctl set-default graphical.target
root
:
#
systemctl set-default multi-user.target
9.3.4. No Graphical User Interface Present
9.3.5. X Server Crashing After User Logs In
$
df -h
/home
partition. The following is a sample output of the df
command:
Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_rhel-root 20G 6.0G 13G 32% / devtmpfs 1.8G 0 1.8G 0% /dev tmpfs 1.8G 2.7M 1.8G 1% /dev/shm tmpfs 1.8G 1012K 1.8G 1% /run tmpfs 1.8G 0 1.8G 0% /sys/fs/cgroup tmpfs 1.8G 2.6M 1.8G 1% /tmp /dev/sda1 976M 150M 760M 17% /boot /dev/dm-4 90G 90G 0 100% /home
/home
partition is full, which causes the crash. You can make some room on the partition by removing unneeded files. After you free up some disk space, start X using the startx
command.
df
and an explanation of the options available (such as the -h
option used in this example), see the df(1)
man page.
9.3.6. Is Your RAM Not Being Recognized?
free -m
command. If the displayed total amount of memory does not match your expectations, it is likely that at least one of your memory modules is faulty. On BIOS-based systems, you can use the Memtest86+ utility to test your system's memory - see Section 22.2.1, “Loading the Memory (RAM) Testing Mode” for details.
Note
free
command. For details about kdump and its memory requirements, see the Red Hat Enterprise Linux 7 Kernel Crash Dump Guide.
mem=
kernel option.
Procedure 9.7. Configuring the Memory Manually
- Start your computer and wait until the boot loader menu appears. If you set your boot loader timeout period to 0, hold down the Esc key to access it.
- When the boot loader menu appears, use your cursor keys to highlight the entry you want to boot and press the e key to edit this entry's options.
- In the list of options, find the kernel line - that is, the line beginning with the keyword
linux
(or, in some cases,linux16
). Append the following option to the end of this line:mem=xxM
Replace xx with the amount of RAM you have in MiB. - Press F10 or Ctrl+X to boot your system with the edited options.
- Wait for the system to boot and log in. Then, open a command line and execute the
free -m
command again. If total amount of RAM displayed by the command matches your expectations, append the following to the line beginning withGRUB_CMDLINE_LINUX
in the/etc/default/grub
file to make the change permanent:mem=xxM
Replace xx with the amount of RAM you have in MiB. - After you updated the file and saved it, refresh the boot loader configuration so that the change will take effect. Run the following command with root privileges:
#
grub2-mkconfig --output=/boot/grub2/grub.cfg
/etc/default/grub
, the above example would look similar to the following:
GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR="$(sed 's, release.*$,,g' /etc/system-release)" GRUB_DEFAULT=saved GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="rd.lvm.lv=rhel/root vconsole.font=latarcyrheb-sun16 rd.lvm.lv=rhel/swap $([ -x /usr/sbin/rhcrashkernel.param ] && /usr/sbin/rhcrashkernel-param || :) vconsole.keymap=us rhgb quiet mem=1024M" GRUB_DISABLE_RECOVERY="true"
9.3.7. Is Your System Displaying Signal 11 Errors?
rd.live.check
boot option at the boot menu. See Section 22.2.2, “Verifying Boot Media” for details.
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