HP StorageWorks External Storage XP user guide for the XP12000, XP10000, SVS200 (T1706-96009, October 2007)

• You cannot execute the Disconnect Subsystem or Disconnect Volume command for external LUs
that include LDEVs for which Auto LUN XP's migration processing is in progress.
• When executing the Disconnect Subsystem or Disconnect Volume command, the displayed
information for Ex-Dev. Status in the Device list becomes Cache Destage. Even if there is no data
left in cache memory, the displayed status stays Cache Destage until the Disconnect Subsystem or
Disconnect Volume command processing is complete.
• When the Disconnect Subsystem or Disconnect Volume command is executed and all data in
cache memory is written to the external LU, the displayed information for Ex-Dev. Status in
the Device list becomes Disconnect.
• When using the mapped external LU from the mainframe OS, set the Missing Interrupt Handler
(MIH) timer to 45 seconds, which is the recommended value.
• In the internal processing, the external LU's RAID level is handled as RAID-1 across the board.
A bar (–) appears on the Command View XP or XP Remote Web Console panes. The external
LU's RAID level is reported as RAID-1 when information about the external array is reported to
higher-level devices (OS).
•Table4and Table 5 show the recommended application level for the mapped external LU
according to the external LU's HDD type.
Table 4 When external LU's emulation type is OPEN
HDD type
Application
FC HD-FC S-ATA
Database
Online Transaction Processing (OLTP)
Not Recommended Not Recommended
File operation from host
(both Read and Write)
OK
Not Recommended
File operation from host
(mainly Read)
OK OK
Backup
OK
Recommended
Archive
OK
Recommended
Table 5 When external LU's emulation type is for mainframes
HDD type
Application
FC HD-FC S-ATA
Database
Online Transaction Processing (OLTP)
Not Recommended Not Recommended
System volumes
(Journal, Check points)
Not Recommended Not Recommended
Operation from TPF
NotSupported NotSupported
File operation from host
(both Read and Write)
OK
Not Recommended
File operation from host
(mainly Read)
OK OK
Backup
OK
Recommended
Archive
OK
Recommended
• 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.
External Storage XP user guide
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