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

HDLM uses the same algorithms to select the path that will be used next,
regardless of whether automatic or manual path switching is used.
When using the Hitachi AMS/WMS series, HDLM will select the next path to be
used first from among the online owner paths, and then from the online non-
owner paths. When the Universal Storage Platform V/VM, Virtual Storage
Platform, Hitachi AMS2000 series, or Hitachi SMS is being used, all the paths
that access the same LU as the path that is currently being used are
candidates for the switching destination path.
Executing the online operation places the offline path online. For details on
the online operation, see
the path status is changed to online, HDLM selects the path to use in the
same way as for automatic path switching. When the Hitachi AMS/WMS series
is being used, HDLM selects the path to use from online owner paths, and
then from online non-owner paths. When the Universal Storage Platform V/
VM, Virtual Storage Platform, Hitachi AMS2000 Series, or Hitachi SMS is
being used, because all the paths are owner paths, the path to use is not
switched even if you change the path status to online.

Path Status Transition

Of the online and offline statuses described in
Failbacks Using Path Switching on page
divided into two sub-statuses. Each status is described below, categorized
according to whether it is an online or offline status.

The Online Path Statuses

The online path statuses are as follows:
•
Online
I/Os can be issued normally.

The Offline Path Statuses

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.
•
Offline(E)
The status indicating that an I/O could not be issued on a given path,
because an error occurred on the path.
The (E) in Offline(E) indicates the error attribute, which indicates that an
error occurred in the path.
2-14
online (Places Paths Online) on page
6-7.
HDLM Functions
Hitachi Dynamic Link Manager User Guide (for VMware(R))
Performing Failovers and
2-11, the offline status is further
6-11. After
offline (Places