HP StorageWorks XP Remote Web Console Software - Manual (Page 35)

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Operations cannot be performed if some parts of the local array are blocked. In this case,
restore blocked parts of the local array, and retry the operation.
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When using the Thunder 9500V series subsystem as an external array, the following versions
are recommended. If you use a 9500V array with a version that is earlier than the following
versions, the SATA drive information might not display correctly.
◦ For Thunder 9530V, Thunder 9520V, Thunder 9570V: version 0658 or later
◦ For Thunder 9580V, Thunder 9585V: version 1658 or later
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When you use TagmaStore AMS 2000 series (AMS2100/2300/2500) subsystem as an
external disk array, unnecessary load to the external disk array should be avoided. When
the TagmaStore AMS 2000 series subsystem is used as an external disk array, the path mode
between disk array is Multi mode. Therefore, when there are a lot of external paths and
mapping volumes, the load to the external subsystem becomes high and some commands
from host to XP24000 or some commands from XP24000 to the external disk array may time
out.
To keep the load proper, the following is recommended.
◦ Define volumes of each TagmaStore AMS2000 series disk array to set external path
number to two. In that case, set the paths to the ports of each controller of TagmaStore
AMS2000 series subsystem.
◦ Set the queue of commands which are issued at the same time from one AMS2000 series
disk array to 500 or less. The calculation formula to derive the number of the queue
commands per AMS2000 series disk array is shown as follows. (number of queues) x
(number of paths of external volumes) x (number of external volumes which issue commands
at the same time) < 500 For more information about setting the queue of commands (see
“Changing an external array's port setting” (page 116) ).
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When you use external volumes of TagmaStore AMS2000 series disk array with copy software,
the copy operation needs to be distributed to two or more RAID groups. There is an upper
bound to the number of pairs, which can be used for initial copy or resynchronization.
Therefore, the copy operation may focus on a specific RAID group according to the order of
the copy operation when the copy operation is performed to two or more external volumes.
The drive of the TagmaStore AMS2000 series disk array may become a bottleneck, which
causes insufficient performance, when the copy operation focuses on a specific RAID group.
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Do not map multiplatform volumes of external arrays as internal LDEVs.
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After executing the Check Paths & Restore Vol., Disconnect Subsystem, or Disconnect Volume
command, click the Refresh button ( ) on the XP Command View Advanced Edition Software
or Remote Web Console main pane to update the information, and check the current status.
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When the external LU's status is Blockade, execute the Check Paths & Restore Vol. command.
If the Check Paths & Restore Vol. command does not restore the external LU's status, the path
to the external array might be blocked. In this case, see
Troubleshooting External Storage XP
for instructions on restoring the path to the external array.
If the external LU's status remains Blockade even though you restored the path to the external
array and executed the Check Paths & Restore Vol. command, execute the Restore command.
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If you execute the Disconnect Subsystem or Disconnect Volume command when I/Os from the
open system host are in progress, host I/Os to the specified volume are forcibly stopped.
When executing the Disconnect Subsystem or Disconnect Volume command, stop host I/Os,
and unmount the volume from the host.
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If the volume is online from the mainframe host, you cannot execute the Disconnect Subsystem
or Disconnect Volume command. Stop host I/Os to the volume, and perform the Vary Offline
operation.
Limitations on XP External Storage operations 35