Chapter 3 Multipath Driver Functions and Operation
3.1 Path Management
FUJITSU Storage ETERNUS Multipath Driver V2 User’s Guide for Linux
Copyright 2014 FUJITSU LIMITED
P2U3-0031-15ENZ0
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3.1.2
Checks and Path Status Transitions
The following three types of checks are performed. The check interval cannot be changed.
In the warning status, the transition to another status is determined by the error counter.
■
Check in active/standby
Active/Standby status paths are checked every 10 minutes.
When a failure is detected by the check, the status changes to either warning or fail. The warning error
counter is determined by the failure cause. The status may change directly to fail if the detected failure is
sufficiently serious.
The status changes in the same way when an error is detected during a normal I/O process.
■
Check in warning
Warning status paths are checked every minute.
When a failure is detected by the check, 10 is added to the error counter. When it is normal, 10 is deducted.
If the error counter reaches 0, the status becomes active/standby. If it reaches 200, the status becomes fail.
■
Check in fail
Fail status paths are checked every 10 minutes.
When a failure is detected by the check, the status does not change. When it is normal, the error counter is set
to 100 and the status becomes warning.
Target path status
Check interval
Post check status
Transition trigger
active/standby
10 minutes
active/standby
Checked normal.
warning
Checked failure. 0 < Error counter < 200
fail
Checked failure. Error counter == 200
warning
1 minutes
active/standby
Checked normal. Error counter == 0
warning
Check result: 0 < Error counter < 200
fail
Checked failure. Error counter == 200
fail
10 minutes
warning
Checked normal. Error counter == 100
fail
Checked failure. Error counter == 200
