HiCommand Dynamic Link Manager (HDLM) for Windows Systems User's Guide (HIT5201-96001, January 2008)

HiCommand
®
Dynamic Link Manager (HDLM) for Windows
®
Systems User’s Guide 31
2.7.3 Path Status Transition
This section explains the online and offline path statuses described in section 2.7. There are
four types of online status, and three types of offline status. A description of each type of
status is provided below. In the descriptions, an offline operation refers to performing an
offline operation using the Path Management window in HDLM GUI or by executing the
dlnkmgr command's offline operation. For details on the offline operation, see section
7.4.
2.7.3.1 The Online Path Status
The online path statuses are as follows:
– Online
I/O can be issued normally.
– Online(P)
A state in which offline processing, for a path in the Online status, is in the
waiting-to-execute status.
This status occurs in a cluster configuration only.
The Online(P) status indicates that the user performed an offline operation on an
Online path that is connected to an LU for which reserve processing was being
performed. I/O operations can be issued normally until such reserve processing
finishes. After the reserve processing finishes, the offline operation is performed and
the path status becomes Offline(C).
The (P) indicates the pending attribute, which indicates that the offline operation
on the path has a waiting-to-execute status.
– Online(E)
An error has occurred on the path and, among the paths that access the same LU,
none of those are in the Online status.
If none of the paths accessing a single 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, by
making sure that all paths are not offline.
The (E) indicates the error attribute, which indicates that an error occurred in the
path.
– Online(EP)
The status of an Offline(P) path changes to Online(EP) when the path goes
through the following process during reserve processing in a cluster configuration:
– When two paths are connected to an LU, and then the user performs an offline
operation on the Offline(E) path to change it to Offline(P).
The other path is Online(E).
– When one of the paths is Offline(P), the other path is Online(E), and HDLM
detects an error in the Online(E) path, then the path statuses change as
follows:
The Online(E) path changes to Offline(E).