Path Status Transition; The Online Path Status; The Offline Path Status - Hitachi XP P9500 User Manual

owner paths. When the Lightning 9900V series, Hitachi USP, Universal
Storage Platform V/VM, Virtual Storage Platform, Hitachi AMS2000 series, or
Hitachi SMS is being used, all paths that access the same LU are candidates
for the switching destination path. All other paths that run through the same
physical path are switched.
Executing the online operation places the offline path online. For details on
the online operation, see
the path status is changed to online (by executing the online operation),
HDLM selects the path to use in the same way as for automatic path
switching. When using the Thunder 9500V series, or Hitachi AMS/WMS series,
HDLM selects the path to use from online owner paths, and then from online
non-owner paths. When the Lightning 9900V series, Hitachi USP, Universal
Storage Platform V/VM, Virtual Storage Platform, Hitachi AMS2000 series, or
Hitachi SMS is being used, since all the paths are owner paths, the path to
use is not switched even if you change the path status to online by using the
online operation.

Path status transition

Each of the online and offline statuses described in
Failbacks Using Path Switching on page 2-13
statuses. The following explains the two online path statuses and the two
offline statuses.

The online path status

The online path statuses are as follows:
•
Online
I/Os can be issued normally.
•
Online(E)
An error has occurred on the path, but none of the other paths that
access the same LU are in the Online status.
If none of the paths accessing a particular LU are in the Online status,
one of the paths is changed to the Online(E) status. This ensures that
the LU can be accessed through at least one path.
The (E) means error, which indicates that an error has occurred on the
path from some previous operation.

The offline path status

The offline path statuses are as follows:
•
Offline(C)
The status in which I/O cannot be issued because the offline operation
was executed. For details on the offline operation, see
Paths Offline) on page
The (C) indicates the command attribute, which indicates that the path
was placed offline by using the command.
online (Places Paths Online) on page
6-6.
HDLM Functions
Hitachi Dynamic Link Manager User Guide (for AIX(R))
6-11. After
Performing Failovers and
is further subdivided into two
offline (Places
2-19