Chapter 6 RAID Group Management
6.2 Functions in the Action Area for RAID Group
ETERNUS Web GUI User’s Guide
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3 Click the [OK] button.
→ RAID group expansion starts.
4 Click the [Done] button to return to the [RAID Group] screen.
End of procedure
6.2.6 Modify RAID Group Parameters
This function tunes the following parameters of each RAID group.
• DCMF
DCMF is a coefficient for the command issuance amount of the drive. Specify this parameter to improve the
sequential writing access performance. The bigger the value is, the more commands issue. Specify the
DCMF according to the RAID group operation.
• Rebuild Priority
Specify the level to give priority to rebuild, copyback, and redundant copy instead of host access. Specifying
a larger "Rebuild Priority" value may improve rebuild, copyback, and redundant copy performance.
• Throttle
Throttle is the proportion of the number of commands that are issued to a drive at the same time to the
maximum number of commands that can be issued. By limiting the number of commands that are issued
at the same time to the drive, the load on the specific RAID group (drive) is reduced.
• Ordered Cut
Ordered Cut is the number of commands for optimizing drive access processing (priority control). By
performing the priority control of commands in increments of the specified number, a long queue time for
low-priority commands can be eliminated.
An error screen appears in the following conditions:
• When the drive layout is incorrect
• The number of selected drives exceeds the available maximum number