Modify REC Multiplicity

Overview

This function specifies multiplicity or priority level when performing REC.

It is not necessary to change the default value (Automatic) for normal use. This function can adjust the copy performance to give priority to REC over work I/O or to reduce the affect on work I/O.

When the Local Storage System and the Remote Storage System are Connected by Remote Connection

If "Automatic" is selected for the specification mode, REC is performed with the recommended multiplicity that is calculated by the obtained round trip time.

If the round trip time is not measured, "***" is displayed in the "Recommended Multiplicity" field.

To display the recommended multiplicity, use the [Get Round Trip Time] function.
If "Manual" is selected for the specification mode, REC will be performed with the specified multiplicity.

When the Local Storage System and the Remote Storage System are Connected by Direct Connection

When the priority level is "Automatic", REC is performed using the priority level that is specified with the [Modify EC/OPC Priority] function.
When the priority level is from "1" to "8", REC is performed using the specified priority level.

Caution

Registering the Advanced Copy function license or the Storage Cluster function license (*1) is required to use this function.

*1 : The Storage Cluster function license must be registered using ETERNUS SF Storage Cruiser.
If "***" is displayed in the "Recommended Multiplicity" field of the Remote Box ID List, and "Automatic" has been selected for the specification mode, REC will not be performed with the appropriate multiplicity. To select "Automatic", measure the round trip time in advance. Refer to the [Measure Round Trip Time] function for details.
If the path between local and remote storage systems has been changed, measure the round trip time and set the multiplicity again.

User Privileges

Availability of Executions in the Default Role

Default role	Availability of executions
Monitor
Admin
StorageAdmin
AccountAdmin
SecurityAdmin
Maintainer

Refer to "User Roles and Policies" for details on the policies and roles.

Settings

In this screen, specify the REC Multiplicity.

Remote Box ID List

Item	Description	Setting values
Remote Box ID	The Box ID for the remote storage system is displayed.
Connection Type	The type of connection to the remote storage system that has a path to the local storage system is displayed. Direct Remote
Priority Level	When the "Connection Type" is "Direct", select the priority level. When the "Connection Type" is "Remote", a "-" (hyphen) is displayed. Automatic REC is performed using the priority level (Automatic Priority/High Priority/Middle Priority/Low Priority/Very Low Priority) that is specified with the [Modify EC/OPC Priority] function. 1 - 8 Specify from "1" to "8" for the REC priority level. "1" corresponds to "Very Low Priority", and "8" corresponds to "High Priority" for the [Modify EC/OPC Priority] function.	Automatic 1 (corresponds to "Very Low Priority") 2 (corresponds to "Low Priority") 3 4 5 6 7 8 (corresponds to "High Priority") "-" (hyphen)
Specification Mode	When the "Connection Type" is "Remote", select the specification mode for multiplicity. When the "Connection Type" is "Direct", a "-" (hyphen) is displayed.	Automatic Manual "-" (hyphen)
Multiplicity	When the "Connection Type" is "Remote" and "Manual" is selected for the specification mode, specify multiplicity (1 to 1024). When "Automatic" is selected, a "-" (hyphen) is displayed. When the "Connection Type" is "Direct", a "-" (hyphen) is displayed. 1 (Default) - 1024 "-" (hyphen)
Present multiplicity	The current multiplicity setting (1 to 1024) is displayed. When the specification mode is "Automatic", "Automatic" is displayed. When the "Connection Type" is "Direct", a "-" (hyphen) is displayed.
Recommended Multiplicity	The recommended multiplicity (1 to 1024) is displayed. If the round trip time is not measured, "***" is displayed in the "Recommended Multiplicity" field. When the "Connection Type" is "Direct", a "-" (hyphen) is displayed.

Advanced Setting

In this screen, specify the copy schedule mode for each remote storage system.

Item

Description

Setting values

Remote Box ID

The Box ID for the remote storage system is displayed.

Copy Schedule Mode

Select the REC copy schedule mode for each remote storage system. It is not necessary to change the default value (Session Balancing) for normal use.

Session Balancing

Copy sessions are scheduled evenly to each Controlling CM for a copy source RAID group (a RAID group to which the copy source volume belongs).
Destination RAID Group Balancing

Only one copy session can be performed for each copy destination RAID group. This method prevents unequal loading on a specific RAID group. This may improve the copy performance when the copy source storage system and the copy destination storage system are connected by direct connection and the copy destination RAID group is configured by Nearline disks.

Caution

Copy performance is not improved by selecting "Destination RAID Group Balancing" in the following conditions:
- When the type of the copy destination volume is not "Standard"
- When the copy destination volume "Standard" and concatenated
Specify the same copy schedule mode for copy source and copy destination storage systems. If different modes are specified, the copy performance may not improve as expected.

Session Balancing (Default)

Destination RAID Group Balancing

Operating Procedures

Click the [Modify REC Multiplicity] in [Action].
Specify the parameters, and click the [Set] button.
→ A confirmation screen appears.
Caution
- When "Manual" is selected for "Specification Mode" and numeric characters exceed the allowed range (from 1 to 1024), an error screen appears.
Note
- Click [Advanced Setting] to specify the copy schedule mode.
Click the [OK] button.

→ The REC multiplicity settings starts.
Click the [Done] button to return to the [Copy Path] screen.