HP StorageWorks XP Remote Web Console Software - Manual (Page 25)

External Storage XP user guide 25
Limitations concerning External Storage XP operations
General limitations
• With the exception of MSA, a host can directly access external disk array volumes that have not been
mapped as local disk array volumes.
• Mapping operations cannot be performed if some parts of the local disk array are blocked. In this
case, restore blocked parts of the local disk array, and retry the operation.
• External LUs can be used immediately after performing mapping operations. To optionally initialize the
data area for the LU, format the LU using Volume Management. For more information, see the
HP StorageWorks LUN Configuration and Security Manager XP User Guide for the
XP10000/XP12000. An external LU can be used for manual Auto LUN XP operations, but not for
automatic Auto LUN XP operations.
• For External Storage XP, IO Suppression mode is typically set to Disable. You cannot use a mapped
external LU with IO Suppression mode set to Enable for pair copy operations in Continuous Access XP,
TrueCopy for z/OS, Continuous Access XP Journal, Universal Replicator for z/OS, Business Copy XP,
ShadowImage for z/OS, or Snapshot XP.
• Host access to the external storage LU must be via the XP10000/XP12000, and must not be via a
direct physical connection to the external storage device LU. For external disk array LUs not involved
with External Storage XP, direct access from a host is allowed for all supported external storage except
MSA. If you use MSA as external storage, it must be entirely dedicate as external storage.
• For all external storage, either set the ES XP cache mode option in Command View XP or XP Remote
Web Console to cache disabled or partition resources associated with external storage in its own CLPR
(for example, CLPR1). While HP strongly recommends this new default for all external storage in
general, this new default is mandatory for any external disk array that is slower than an XP12000
external port (for example, the Modular Smart Array product line) unless it resides in its own CLPR
partition with isolated port/MP/cache resources.
• If the host connected to the local disk array issues too many I/Os for the external disk array to process,
commands from the host might time out.
Maximum number of external LUs that can
be connected
15,360 for the XP12000
8,192 for the XP10000
1,024 volumes can be connected per port
NOTE: If you use Snapshot XP, the number of external LUs that can
be connected is as follows:
• For the XP12000:
Number of external LUs + Number of virtual LUs
≤ 15,360
• For the XP10000:
Number of external LUs + Number of virtual LUs
≤ 8,192
Maximum number of FC paths that can exist
to one external LU
8
Maximum capacity of an external LU 2 TB per external LU (OPEN-V)
If you specify an external LU that is larger than 2 TB, you can only
access data stored in the field up to 2 TB.
Minimum capacity of an external LU 35 MB per external LU (non-OPEN-V)
When the emulation type of the volume is OPEN-V, minimum
capacity is 46.86 MB per external LU.
Table 3 External Storage XP requirements (continued)
Item Requirement