HP Hitachi Dynamic Link Manager Software - Manual (Page 53)

2. HDLM Functions
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Executing the online operation places the offline path online. For details on the
online
operation, see 6.5 online (Places Paths Online). After a path status is
changed to online, the path can be selected as a useable path by HDLM in the same
manner as 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 9900 series, 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.
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 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 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.
(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) indicates the command attribute, which indicates that the path was placed
offline by using the command.
•
Offline(E)