3 path status transition – HP Hitachi Dynamic Link Manager Software User Manual
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2. HDLM Functions
27
Executing the
online
operation places the offline path online. For details on the
online
operation, see 6.5 online (Places Paths Online). After the path status is
changed to online, HDLM selects the path to use in the same way as for automatic path
switching. When the Thunder 9500V Series, or 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 Lightning 9900 Series, Lightning 9900V Series, Hitachi
USP, 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.
2.8.3 Path Status Transition
Each of the online and offline statuses described in 2.8 Performing Failovers and
Failbacks Using Path Switching is further subdivided into two statuses. The following
explains the two online path statuses and the two offline path statuses.
(1) The Online Path Status
The online path statuses are as follows:
•
Online
I/Os can be issued normally.
•
Online(E)
An error has occurred in the path. Also, none of the paths that access the same LU
are in the
Online
status.
If none of the paths accessing a single LU are in the
Online
status, one of the
paths will be changed to the
Online(E)
status. All the paths that access the same
LU will not be in the offline statuses. This ensures access to the LU.
The text (E) of Online(E) indicates the error attribute, which indicates that an
error occurred in the path.
(2) 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 6.4 offline (Places Paths
Offline).
The (C) means command, 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