Hitachi Dynamic Link Manager Software Users Guide for Windows (6.6) (HIT5201-96005, April 2011)

2. HDLM Functions
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Hitachi USP, 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.
By changing the path status to online in the Path Management window, or by executing
the
online operation, an offline path can be placed 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
Path Management window or the
online operation.
For details on how to change the path status in the Path Management window, see the
HDLM GUI Help.
2.7.3 Path Status Transition
This subsection explains the online and offline path statuses described in
2.7 Performing Failovers and Failbacks Using Path Switching. There are four types
of online statuses, and three types of offline statuses. Each type is described below. In
the descriptions, an offline operation refers to performing an offline operation by using
the Path Management window in the HDLM GUI, or by executing the
dlnkmgr
command's
offline operation. For details on the offline operation, see 6.4 offline
(Places Paths Offline).
(1) The Online Path Statuses
The online path statuses are as follows:
•
Online
I/Os can be issued normally.
•
Online(P)
A state in which a path in the
Online status is in the waiting-to-execute status to
be taken offline.
This status occurs in a cluster configuration only.
The
Online(P) status indicates that the user has requested an Online path to be
taken offline, for a path that is connected to an LU that is currently performing
reserve processing. I/O operations can still be issued normally until the reserve
processing on the LU finishes. After the reserve processing finishes, the offline
operation request will be performed and the path status will become