When External Lu's Emulation Type Is For Mainframes - HP StorageWorks XP12000 User Manual

Table 4 When external LU's emulation type is OPEN (continued)
Application
File operation from host
(mainly Read)
Backup
Archive
Table 5

When external LU's emulation type is for mainframes

Application
Database
Online Transaction Processing (OLTP)
System volumes
(Journal, Check points)
Operation from TPF
File operation from host
(both Read and Write)
File operation from host
(mainly Read)
Backup
Archive
• The external array's performance and status affect the mapped external LU's Read and Write
performance. If there is a heavy load on the external array, the Read and Write operation's processing
speed slows. In this case, I/Os from the mainframe host might have an MIH error.
• If the host connected to the local array issues too many I/Os for the external array to process,
commands from the host might time out.
When the amount of I/Os from the host to the external LU exceeds the maximum amount of I/Os the
external array can accept, commands from the host to the local array might time out. As you configure
the system using external LUs, consider the external array's I/O capacity.
• When executing commands in HP StorageWorks software products to the mapped external LU and,
therefore, too many I/Os are issued for the external array to process, commands might time out and
errors might occur.
When the amount of I/Os from the software products to the external LU exceeds the maximum amount
of I/Os the external array can accept, commands might time out and errors might occur. As you
configure the system using external LUs, consider the external array's I/O capacity.
• When using an external LU from the host, note the external LU's Path Blockade Watch time. If the Path
Blockade Watch time is longer than the host command's timeout period, commands from the host might
time out when the power supply is off or errors occur for the external array. If host I/O is a significant
concern, ensure that the external LU's Path Blockade Watch time is the same as or shorter than the host
command's timeout period.
• Host access to the external storage LU must be via the local array, and must not be via a direct physical
connection to the external storage device LU. For external 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.
36 Preparing for External Storage XP operations
HDD type
FC S-ATA
OK OK
OK Recommended
OK Recommended
HDD type
FC S-ATA
Not Recommended Not Recommended
Not Recommended Not Recommended
Not Supported Not Supported
OK Not Recommended
OK OK
OK Recommended
OK Recommended