chfcmap

Use the chfcmap command to modify attributes of an existing mapping.

Syntax

Parameters

-name new_name_arg: (Optional) Specifies the new name to assign to the mapping. The -name parameter cannot be used with any other optional parameters.
-consistgrp consist_group_id | consist_group_name: (Optional) Specifies the consistency group for which you want to modify the mapping. To modify a map such that it is stand-alone (not in a consistency group), specify -consistgrp 0.
Restriction: The consistency group cannot be modified if the specified consistency group is in the preparing, prepared, copying, suspended, or stopping state.
-copyrate rate: (Optional) Specifies the copy rate. The rate value can be 0 - 150. The default value is 50. A value of 0 indicates no background copy process. For the supported -copyrate values and their corresponding rates, see the table in the description.
-autodelete on | off: (Optional) Specifies that the autodelete function be turned on or off for the specified mapping. When you specify the -autodelete on parameter, you delete a mapping after the background copy is completed. If the background copy is completed, the mapping is deleted immediately.
-cleanrate rate: (Optional) Sets the cleaning rate for the mapping. The rate value can be 0 - 150. The default value is 50.
fc_map_id | fc_map_name: (Required) Specifies the ID or name of the mapping to modify. Enter the ID or name last on the command line.

Description

The chfcmap command modifies attributes of an existing mapping.

Important: You must enter the fc_map_id | fc_map_name last on the command line.

If you have created several FlashCopy® mappings for a group of volumes that contain elements of data for the same application, you can assign these mappings to a single FlashCopy consistency group. You can then issue a single prepare command and a single start command for the whole group, for example, so that all of the files for a particular database are copied at the same time.

The -copyrate parameter specifies the copy rate. If 0 is specified, background copy operations are disabled. The -cleanrate parameter specifies the rate for cleaning the target volume. The cleaning process is active only if the mapping is in the copying state and the background copy has completed, the mapping is in the copying state and the background copy is disabled, or the mapping is in the stopping state. You can disable cleaning when the mapping is in the copying state by setting the -cleanrate parameter to 0. If the -cleanrate is set to 0, the cleaning process runs at the default rate of 50 when the mapping is in the stopping state to ensure that the stop operation can be completed.

The following table describes the relationship of the copy rate and cleaning rate values to the attempted number of grains to be split per second. A grain is the unit of data represented by a single bit.

Table 1. Relationship between the rate, data rate, and grains per second values
User-specified rate attribute value	Data copied/sec	256 KB grains/sec	64 KB grains/sec
1 - 10	128 KB	0.5	2
11 - 20	256 KB	1	4
21 - 30	512 KB	2	8
31 - 40	1 MB	4	16
41 - 50	2 MB	8	32
51 - 60	4 MB	16	64
61 - 70	8 MB	32	128
71 - 80	16 MB	64	256
81 - 90	32 MB	128	512
91 - 100	64 MB	256	1024
101 - 110	128 MB	512	2048
111 - 120	256 MB	1024	4096
121 - 130	512 MB	2048	8192
131 - 140	1 GB	4096	16384
141 - 150	2 GB	8192	32768

Restriction: Maps that are rc_controlled are not shown in the view after this command is processed.

Note: For FlashCopy mappings that are used for policy-based replication, the chfcmap command can fail. These mappings are system-owned and are created automatically as part of the policy-based replication. However, you can change the -copyrate and -cleanrate parameters of a reverse mapping and also change the -cleanrate parameter on a forward mapping.

An invocation example

chfcmap -name testmap 1

The resulting output:

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