HP XP P9500 Storage - Manual (Page 40)

You can manually place a path online or offline by doing the following:
• Use the HDLM GUI Path Management window.
• Execute the dlnkmgr command's online or offline operation.
For details on the online operation, see
online (Places Paths Online) on
page 6-11 . For details on the offline operation, see offline (Places
Paths Offline) on page 6-6 .
However, if there is only one online path for a particular LU, that path cannot
be manually switched offline. Also, a path with an error that has not been
recovered from yet cannot be switched online.
HDLM uses the same algorithms to select the path that will be used next,
regardless of whether automatic or manual path switching is used.
When using the Thunder 9500V series, or Hitachi AMS/WMS series, HDLM will
select the next path to be used first from among the online owner paths, and
then from the online non-owner paths. When the Lightning 9900 series,
Lightning 9900V series, Hitachi USP series, Universal Storage Platform V/VM
series, Virtual Storage Platform series, Hitachi AMS2000 series
# , Hitachi SMS
series # , HUS100 series # , or HUS VM 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 online (Places Paths Online) on page
6-11 . 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 series, Universal Storage Platform V/VM series, Virtual Storage Platform
series, Hitachi AMS2000 series
# , Hitachi SMS series # , HUS100 series # , or
HUS VM 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.
#
This storage system applies when the dynamic I/O path control function is
disabled.
Path Status Transition
Each of the online and offline statuses described in Performing Failovers and
Failbacks Using Path Switching on page 2-17 is further subdivided into
several statuses. The path statuses (the online path statuses and offline path
statuses) are explained below.
2-20
HDLM Functions
Hitachi Dynamic Link Manager User Guide for Windows ®