Kernel Panic - Not Syncing: Fatal Exception

Document ID : KB000103283
Last Modified Date : 25/06/2018
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Issue:
The Multi-Port Monitor uses two XFS file systems to accommodate the Vertica metrics database (/NQXFS) and the storage of raw packets (/DATA). These file systems often become corrupt on the CA6000 machines.

Typical kernel panic message:

User-added image
Environment:
CentOS 5.X, 6.X
Cause:
Due to the extremely high read/write speeds and the servers being equipped with older RAID controller cards, these file systems are susceptible to corruption.
 
Resolution:
To remedy this issue, you need to boot the machine into single user mode and run xfs repairs on the /nqxfs and /data partitions.

1. Press and hold the power button to restart the appliance.

2. After BIOS scans, the initial CentOS boot screen will appear. Hit any key before the countdown reaches zero seconds to enter the boot menu.

3. The default boot kernel will already be selected. Press ‘a’ to modify kernel boot parameters.

4. The cursor will be at the end of the line of kernel parameters. Add the parameter single to the end of the line, as shown in the example below, and press Enter:
 
‘ro root=LABEL=/ clock=pit nsmp noapic nolapic single’

5. When the kernel finishes booting, a command prompt will be displayed. There is no login prompt as the system is running in single user mode.

Note: In single user mode, the appliance can only be accessed from the terminal display.

6.
/nqxfs partition
‘umount /nqxfs’
‘xfs_repair /dev/sda4’
/data partition
‘umount /data‘
‘xfs_repair /dev/sdb1’
 
7. Enter ‘reboot’ to leave single user mode and restart the appliance.

8. Verify the repair was successful and the server has returned to normal operation