HP XP P9500 Storage - Manual (Page 50)

4. Start the read or write I/O to the local storage system.
All read and write I/Os with fibre channel connections should be started.
Disconnecting external storage system or external volume
Use the Disconnect External Storage Systems command and the Disconnect External Volumes
command to disconnect the external volume. You need to disconnect the external volume(s), for
example, before you turn the power supply off of the local storage system or the external storage
system for maintenance, or before you delete the external volume mapping. In addition, before
you access the mapped external volumes from the external storage system, disconnect the external
volumes. After you finish using the external volumes from the external storage system and need to
access the external volumes from the local storage system, resume using the external volumes by
following the procedure in
“Checking connection status and resuming external volume operation”
(page 52) .
As you execute the Disconnect External Storage Systems or the Disconnect External Volumes
command, the mapped external volume stops accepting host I/O, and all the data in the cache
memory is written into the external volume (all the data is destaged).
The settings of the mapping are preserved, even though the external volume is disconnected using
the Disconnect External Storage Systems command or the Disconnect External Volumes command.
Therefore, you can resume using the external volume as a mapped volume with the former settings,
even though once you have disconnected the external volume.
The following table describes operations that are required before disconnecting external volumes.
Table 4 Operations required before disconnecting external volumes
This operation is required If External Volume is Used in this way
Stop the host I/Os to the volume and unmount from the host. I/Os to the external volume from the
open system host are in progress.
The host I/Os to the specified volume are forcibly stopped if you disconnect
an external volume when I/Os from the open system host are in progress.
Stop the host I/Os to the volume and perform the Vary Offline operation. The external volume is online from the
mainframe host.
Delete the pairs. The external volume includes the LDEVs
that are set as the pair of the copy
program products*.
However, you can disconnect external volumes without deleting pairs when
the Business Copy pair status is PSUE or when the Business Copy Z pair
status is Suspend.
Change the status of the Snapshot pair to PAIR. The external volume includes the LDEVs
that are registered to a pool for Snapshot
as pool volumes.
Perform the following operations on all the Thin Provisioning volumes (V-VOLs)
that are associated with a pool to which the external volume is registered. The external volume includes the LDEVs
that are registered to a pool for Thin
Provisioning as pool volumes.
• Stop the use of the Thin Provisioning volumes.
•
Block the Thin Provisioning volumes by using the Virtual LVI/Virtual LUN
function for blocking volumes.
Delete the migration plans. The external volume includes the LDEVs
for which the migration processing of
Auto LUN is in progress.
*The copy program products include Business Copy, Business Copy Z, Continuous Access Journal,
Continuous Access Journal Z, Continuous Access Synchronous, Continuous Access Synchronous
Z, and Snapshot.
50 Performing External Storage operations