Hitachi XP P9500 User Manual page 43

When the following conditions are all 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 operations issued to an LU is
¢
successful.
#5
During reserve processing for an LU, the Offline(E) status is temporarily
changed to Offline(P). After the reserve processing finishes, the
Offline(P) status is changed to Offline(C).
#6
When the following conditions are satisfied, the connected Offline(E)
paths are automatically placed online:
All the online paths are Online(E) and all the SCSI devices connected
¢
to the Online(E) paths have been deleted.
The Offline(E) paths are assumed to have had an intermittent error,
¢
and are thus excluded from automatic failbacks.
The SCSI devices are connected to the Offline(E) paths.
¢
If there is only one available online path for an LU, it cannot be placed offline
by using the Path Management window or by executing the offline
operation. This ensures that the LU can always be accessed by at least one
path. For details on the offline operation, see
on page 6-6.
If an error occurs in the only available online path for an LU, the status of the
path will change to Online(E).
If you are using the automatic failback function, after the path has recovered
from the error, HDLM will automatically place the path online. There are,
however, the following exceptions:
• When you are using intermittent error monitoring, sometimes, the path in
which the intermittent error occurred is not automatically placed online
after the path has been recovered from the error. If this happens,
manually place the path online. If the only other online path is in the
Online(E) status when the path is recovered from the error, the path
recovered from the error might be placed online automatically. For
details, see Figure 2-13 What Will Happen When an Intermittent Error
Does Not Occur on a Path on page
• There are cases in which the path is automatically placed online even if
you are not using the automatic failback function. If a piece of hardware
that supports the Windows plug-and-play function is removed, HDLM will
place the path associated with that hardware offline, as well. If the
Hitachi Dynamic Link Manager User Guide (for Windows(R))
2-26.
HDLM Functions
offline (Places Paths Offline)
2-23