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3 path status transition – HP Hitachi Dynamic Link Manager Software User Manual

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2. HDLM Functions

28

other paths that run through the same physical path are switched.
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 (by executing the

online

operation), HDLM selects the path to use

in the same way as for 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 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.

2.7.3 Path status transition

Each of the online and offline statuses described in 2.7 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.