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An RH2285 OS Cannot Be Started

Publication Date:  2015-06-19 Views:  101 Downloads:  0
Issue Description
Hardware configuration:
RH2285 server, 12 hard disks, and 1068E controller card

Software configuration:
SUSE11 sp1 (64-bit)

Symptom:

After the server OS enters kdump, the system displays Waiting for device /dev/sda6 to appear shown in the red box in Figure 1.

Figure 1 Failure in finding the sda6 root partition


Handling Process
1.  Run the echo c > /proc/sysrq-trigger command to crash the system. Then errors in Figure 1 may occur.

2.  Based on the dmesg information, the problem is caused because the mptsas driver is loaded for about 10 minutes (30s by default).

3.  The system is crashed and enters the kdump process. The process finds storage devices. The input/output (I/O) Advanced Programmable Interrupt Controller (APIC) receives the interruption from a device related to the I/O APIC, generates interruption information, and sends the interruption information to the local APIC of the processor. After processing the information, the processor drives the device. Then use the read partition information to identify storage devices in partitions and mount the root partition. See Figure 2.

Figure 2 Process for handling system crash




4.  In kdump, the memory in the core serves as the crash storage kernel, and only one processor is reserved. When the I/O APIC distributes the interruption information, an incorrect operation occurs, that is, the information is sent to the local APIC of a nonexistent processor, which causes failures in distributing the interruption information. The driver accesses the sda6 root partition in cycled mode. When the accessing times out, the driver stops accessing the partition, and a message showing that the information is sent to a nonexistent processor is displayed.
Root Cause
The root cause is the SUSE11 bug. The I/O APIC is not used for interruption information distribution in the OS kdump process. The information is sent to the active processor to shield exceptions during information distribution, find storage devices, and store the driver and faults.

Solution
To resolve the problem, do as follows:
  1. Run vim /etc/sysconfig/kdump.
  2. Add noapic to KDUMP_COMMANDLINE_APPEND.
  3. Recreate the initrd file of the kdump process.

END