Limitations On External Storage Xp Operations; Example Of External Lu With 2 Tb Or Less - HP StorageWorks User Manual

Limitations on External Storage XP operations

• External volumes can be mapped as any CU:LDEV combination from 00:00 to 3F:FF.
• Only ports in SLPR0 can be set as external ports.
• Do not access any external storage volume that is mapped as an External Storage XP volume from a
host connected directly to the external disk array. Also, do not access an External Storage XP mapped
external array volume using the external disk array's functions (for example, local replication). After
mapping an external disk volume as a local XP12000/XP10000 volume, access the mapped external
disk volume only via the local XP12000/XP10000 disk array.
• With the exception of MSA, a host can directly access external disk array volumes that have not been
mapped as local disk array volumes.
• Continuous Access XP P-VOLs, S-VOLs, and journal volumes are not supported on MSA disk arrays.
• HP does not recommend that volumes involved with Snapshot XP reside on external MSA arrays.
• If you map an external LU that is more than 2 TB with the setting of OPEN-V emulation type, you can
access the data stored in the field up to 2 TB. You cannot access the data that is stored in the field over
2 TB.
• When mapping a volume that has a capacity of 2 TB or less in the external disk array and specifying
the OPEN-V emulation type, the LU is defined as an internal XP LDEV with the same capacity as the
mapped external LU. That is, no space is forfeited for management space, and no formatting of that
data occurs. Therefore, OPEN-V is recommended.
Figure 11

Example of external LU with 2 TB or less

• If you map an external LU that is equal to or greater than 575.98 GB with an OPEN emulation type
other than OPEN-V, you can access data stored in the field up to 575.98 GB. You cannot access data
stored in the field over 575.98 GB.
However, for emulation types with a small base capacity, some of the field of 575.98 GB might not be
available. For more information, see
• If you map an external LU that is equal to or greater than 575.98 GB with a 3380 mainframe
emulation type, you can access data stored in the field up to 575.98 GB. You cannot access data
stored in the field over 575.98 GB.
However, for emulation types with a small base capacity, some of the field of 575.98 GB might not be
available. For more information, see
• If you map an external LU that is equal to or greater than 695.98 GB with a 3390 mainframe
emulation type, you can access data stored in the field up to 695.98 GB. You cannot access data
stored in the field over 695.98 GB.
However, for emulation types with a small base capacity, some of the field of 695.98 GB might not be
available. For more information, see
• If you plan to use the mapped external LU from the mainframe OS (volume is mapped with a 3380-x or
3390-x mainframe emulation type), you must select an external LU that consists of one LDEV or you
must first adjust the capacity of the external LU to be mapped. If multiple LDEVs exist in one external LU
and if a lot of I/Os are made to these LDEVs, the read and write commands might timeout. When the
commands timeout, the SIM (21D2xx) is reported.
• When you map an external LU as internal XP LDEVs and use emulation types other than OPEN-V, the
number of volumes and the volume capacity of the mapped internal XP LDEVs depends on the original
external LU's capacity and each emulation type's normal size. When an external LU is mapped using
emulation types other than OPEN-V, an XP array management information area is required in the
32 External Storage XP for the XP12000/XP10000
"Required volume capacity for emulation
"Required volume capacity for emulation
"Required volume capacity for emulation
types" on page 112.
types" on page 112.
types" on page 112.