[T Series]A Failure to Display a Recovered LUN on a Host

Publication Date:  2012-07-19 Views:  78 Downloads:  0
Issue Description
Product and version information:
S5500T V100R001 V100R002
S5600T V100R001 V100R002
S5800T V100R001 V100R002
S6800T V100R001 V100R002


After a LUN recovered from a failure, we ran the fdisk -l command on the Linux host, but could not see the recovered LUN in the output.

Application server operating system: SUSE Linux Enterprise Server 11 (x86_64)
Alarm Information
Handling Process
The situations that could result in an abnormal LUN vary. Therefore, choose one from the following methods according to your actual situation:
If the LUN was mounted to a file system, unmount the LUN and run the hot_add command to scan for disks.
If the LUN was being accessed by an application, close the application and run the hot_add command.
Run the echo 1 > /sys/block/sda/device/rescan command (using sda as an example) to refresh device status. Then run the fdisk -l command to view the LUN.
Root Cause

A LUN failure during I/O operations causes large amounts of I/O errors on the LUN. As a result, the LUN became abnormal.

When we ran the fdisk -l command to list all devices, the fdisk -l command sent an I/O to read the LUN-related information. Since the LUN was already abnormal, the fdisk -l command could not be sent to the LUN. As a result, the LUN was not displayed in the output even if it was recovered from the failure.