Fujitsu ETERNUS Multipath Driver V2, Руководство пользователя

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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 Path Management
3.1.1 Path Status
The Multipath Driver manages the status of each path based on whether the path is available for use by user
I/O request processes. Current path status can be checked using the "iompadm info" command. (Refer to
"3.4
Multipath Status Display" (page 50) for details on iompadm info.)
I/O request ready paths may be classified into the following three ready statuses:
Table 3.1 Path status values
Ready status Description
active
•
Normal operating status (no failures have been detected).
•
If there are two or more active paths, load balancing is performed between them.
•
[active "online"] is displayed by the "iompadm info" command.
standby
•
Path is connected to the non-assigned CM, which is (normally) on standby.
•
If the assigned CM (active) path fails, the standby path becomes the active path.
•
When the assigned CM path returns to active status, this path returns to standby.
•
[standby "online"] is displayed by the "iompadm info" command.
warning
•
I/O errors have been detected on the path, and it is currently being monitored by Auto Path
Check.
•
Warning status paths are checked every minute.
•
Each type of error is allowed a certain number of checks. If a path is determined to be usable
before this limit is reached, its status is reverted to active or standby, otherwise its status is
changed to fail.
•
Warning paths are never used for I/O if an active or standby path is available.
•
If no active or standby path is available, a warning path may be used for I/O.
•
[active "warning"] or [standby "warning"] is displayed by the "iompadm info" command.