No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

Disk Identification Failure Due to Short Disk Replacement Interval

Publication Date:  2014-09-22 Views:  59 Downloads:  0
Issue Description
A replacement SATA disk cannot be identified by the cm process nor is added to an instance group. The fault persists after the disk is reinserted and no related alarm is reported.

The disk is identified by the operating system but not by the Wushan file system.

Alarm Information
None

Handling Process
Remove the newly inserted disk, wait 30 seconds, and insert the disk again.
Pull the disk 2 cm out to disconnect it from the rear panel connector, wait 30 seconds, and slowly insert the disk again.

Root Cause
CM Disk Detection Process

The cm process starts a thread to obtain the current disk state every 10 seconds and compares the obtained disk state with the previous disk state. If the current and previous disk states are different, the cm process reports an event to the ISM to inform the OSN of disk state change.

The current disk state is obtained using a global variable that is refreshed every 10 seconds by a thread. The thread refreshes the variable based on the content in file /proc/partitions.

In this case, a new disk cannot be detected if it is inserted within 10 seconds after the original disk is removed and may not be detected if the time is within 20 seconds.

Therefore, you are advised to insert a new disk at least 20 seconds later after removing the original disk. The recommended interval is 30 seconds.

The disk identification failure may cause the Wushan file system to work without instances, compromising system reliability.

Suggestions
You are advised to insert a new disk at least 20 seconds later after removing the original disk. The recommended interval is 30 seconds.

END