HP Hitachi Dynamic Link Manager Software - Manual (Page 51)

2. HDLM Functions
29
LU.
#2
When the following conditions are satisfied, a path that has been determined to
have an intermittent error also becomes subject to automatic failback:
• All the paths connected to an LU are Online(E), Offline(E), or Offline(C).
• All the paths connected to an LU have been determined to have an
intermittent error.
• The processing of continuous I/O issued to an LU is successful.
#3
When an Online or Offline(E) path exists among the paths that access the same
LU.
#4
One of the Offline(E) paths is changed to the Online(E) path.
#5
When an Offline(E) path exists among the paths that access the same LU.
The last available online path for each LU cannot be placed offline by executing the
offline
operation. This ensures access to the LU. For details on the
offline
operation, see 6.4 offline (Places Paths Offline).
If none of the paths accessing a single LU are in the
Online
status, one of the paths
will be changed to the
Online(E)
status.
If you are using automatic failback, when the path recovers from an error, HDLM
automatically places the path online.
When you are using intermittent error monitoring, the path in which the intermittent
error occurred is not automatically placed online even when the path recovers from the
error. In such a case, place the path online manually.
Note
If there is a path failure immediately after a path is placed offline by using the
dlnkmgr
command, Offline(C) might change to Offline(E). If an offline
operation was performed, wait for a fixed period of time (about 2 minute), check
the path status by using the
dlnkmgr
command, and make sure that the status has
changed to Offline(C). If it is Offline(E), retry the offline operation.