Use the chfcmap command to modify attributes of an existing
mapping.
Syntax
chfcmap [ -namenew_name_arg ] { fc_map_id | fc_map_name }
chfcmap { [ -consistgrp { consist_group_id | consist_group_name } ] | [ -force ] } [ -copyrate rate ] [ -autodelete { on | off } ] [ -cleanrate { rate } ] { fc_map_id | fc_map_name }
Parameters
- -namenew_name_arg
- (Optional) Specifies the new name to assign to the mapping. The -name
parameter cannot be used with any other optional parameters.
- -force
- (Optional) Specifies that the mapping be modified to a stand-alone mapping (equivalent to
creating the mapping without a consistency group ID). You cannot specify the
-force parameter with the -consistgrp
parameter.
Important: Using the force parameter might result in a loss
of access. Use it only under the direction of IBM support personnel.
- -consistgrpconsist_group_id | consist_group_name
- (Optional) Specifies the consistency group for which you want to modify the mapping. You
cannot specify the -consistgrp parameter with the
-force parameter.
Note: The consistency group cannot be modified if the
specified consistency group is in the preparing,
prepared, copying,
suspended, or stopping
state.
- -copyraterate
- (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 Relationship between the rate, data rate, and grains per second values.
- -autodeleteon | off
- (Optional) Specifies that the autodelete function be turned on or off for the specified
mapping. When you specify the -autodelete on parameter, you are deleting
a mapping after the background copy completes. If the background copy is already complete, the
mapping is deleted immediately.
- -cleanraterate
- (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.
Attention: 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 is disabled. The
-cleanrate parameter specifies the rate for cleaning the target volume.
The cleaning process is only active 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
completes.
This table provides 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 |
Note: Maps that are rc_controlled are not shown in the view when this
command is specified.
An invocation example
chfcmap -name testmap 1
The
resulting output:
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