Use the mkfcmap command to create a
new FlashCopy mapping, which maps a source volume to a target volume
for subsequent copying.
Syntax
mkfcmap
-source { src_vdisk_id | src_vdisk_name
} -target { target_vdisk_id | target_vdisk_name
} [ -namenew_name_arg ]
[ -consistgrp { consist_group_id
| consist_group_name } ] [ -copyrate
rate ] [ -autodelete ] [ -grainsize { 64 | 256 }
] [ -incremental
] [ -cleanrate
{ rate }
] [ -iogrp
{ iogroup_name | iogroup_id
} ] [ -keeptarget
]
Parameters
- -sourcesrc_vdisk_id
| src_vdisk_name
- (Required) Specifies the ID
or name of the source volume.
- -targettarget_vdisk_id
| target_vdisk_name
- (Required) Specifies the
ID or name of the target volume.
- -namenew_name_arg
- (Optional) Specifies the name to assign to the new
mapping.
- -consistgrpconsist_group_id
| consist_group_name
- (Optional) Specifies the
consistency group to add the new mapping to. If you do not specify
a consistency group, the mapping is treated as a stand-alone mapping.
- -copyraterate
- (Optional) Specifies the copy rate. The rate value can be 0 - 100. The default value is 50.
A value of 0 indicates no background copy process. For the supported -copyrate values and their corresponding rates, see Table 1.
- -autodelete
- (Optional)
Specifies that a mapping be deleted when the background copy completes.
The default, which applies if this parameter is not entered, is that autodelete is set to off.
- -grainsize 64 | 256
- (Optional) Specifies the grain size for the mapping. The default value is 256. Once set, this value cannot be changed.
Remember: If either the source or target disk contains
compressed copies, the default value is 64 (unless source or target
disk is part of a mapping with grainsize 256 KB).
- -incremental
- (Optional)
Marks the FlashCopy mapping as an incremental copy. The default is
nonincremental. Once set, this value cannot be changed.
- -cleanraterate
- (Optional) Sets the cleaning rate for the mapping.
The rate value can be 0 - 100. The default
value is 50.
- -iogrpiogroup_name | iogroup_id
- (Optional) Specifies the I/O group for the FlashCopy
bitmap. Once set, this value cannot be changed. The default I/O group
is either the source volume, if a single target map, or the I/O group
of the other FlashCopy mapping to which either the source
or target volumes belong.
Note: If not enough bitmap
space is available to complete this command, more space will automatically
be allocated in the bitmap memory (unless you have already reached
the maximum bitmap memory).
- -keeptarget
- (Optional)
Specifies that the target volume and source volume availability should
be kept the same. If the target becomes unavailable the source is
also made unavailable (instead of stopping the FlashCopy mapping).
Description
This command creates a new FlashCopy mapping. This mapping persists
until it is manually deleted, or until it is automatically deleted
when the background copy completes and the autodelete parameter set to on. The source and target
volumes must be specified on the mkfcmap command.
The mkfcmap command fails if the source and target volumes are not identical in size. Issue
the lsvdisk -bytes command to find the exact size
of the source volume for which you want to create a target disk of
the same size. The target volume that you specify cannot be a target
volume in an existing FlashCopy mapping. A mapping cannot be created
if the resulting set of connected mappings exceeds 256 connected
mappings.
The mapping can optionally be given a name and assigned
to a consistency group, which is a group of mappings that can be started
with a single command. These are groups of mappings that can be processed
at the same time. This enables multiple volumes to be copied at the
same time, which creates a consistent copy of multiple disks. This
consistent copy of multiple disks is required by some database products
in which the database and log files reside on different disks.
If the specified source and target volumes are the target and
source volumes, respectively, of an existing mapping, then the mapping
being created and the existing mapping become partners. If one mapping
is created as incremental, then its partner is automatically incremental.
A mapping can have only one partner.
You can create a FlashCopy mapping in which the target
volume is a member of a Metro Mirror or Global Mirror relationship,
unless one of the following conditions applies:
- The relationship is with a clustered system that is running an earlier code level.
- The I/O group for the mapping is different than the I/O group
for the proposed mapping target volume.
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.
Note: You cannot issue this command if the:
- Target volume is a master or auxiliary volume in an active-active relationship
- Source volume is a master or auxiliary volume in an active-active relationship and the target volume and map are not in the same site
as the source volume
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 value and the data copied per
second
| User-specified rate attribute value |
Data copied/second |
| 1 - 10 |
128 KB |
| 11 - 20 |
256 KB |
| 21 - 30 |
512 KB |
| 31 - 40 |
1 MB |
| 41 - 50 |
2 MB |
| 51 - 60 |
4 MB |
| 61 - 70 |
8 MB |
| 71 - 80 |
16 MB |
| 81 - 90 |
32 MB |
| 91 - 100 |
64 MB |
Note: Maps that are rc_controlled are not
shown in the view when this command is specified.
An invocation example
mkfcmap -source 0 -target 2 -name mapone
The resulting output:
FlashCopy Mapping, id [1], successfully created
An invocation example
mkfcmap -source 0 -target 2 -name mapone -keeptarget
The resulting output:
FlashCopy Mapping, id [1], successfully created