The mkfcmap command creates a new FlashCopy® mapping, which maps a source VDisk to a target VDisk for subsequent copying.
Syntax
>>- svctask -- -- mkfcmap -- -----------------------------------> >-- -source --+- src_vdisk_id ---+-- ---------------------------> '- src_vdisk_name -' >-- -target --+- target_vdisk_id ---+-- ------------------------> '- target_vdisk_name -' >--+-------------------------+-- -------------------------------> '- -name -- new_name_arg -' >--+-----------------------------------------+-- ---------------> '- -consistgrp --+- consist_group_id ---+-' '- consist_group_name -' >--+---------------------+-- --+---------------+----------------> '- -copyrate -- rate -' '- -autodelete -' >--+-------------------------+--+----------------+--------------> '- -grainsize --+- 64 --+-' '- -incremental -' '- 256 -' >--+--------------------------+---------------------------------> '- -cleanrate ---- rate ---' >--+------------------------------+---------------------------->< '- -iogrp --+- iogroup_name -+-' '- iogroup_id --'
Parameters
- -source src_vdisk_id | src_vdisk_name
- (Required) Specifies the ID or name of the source VDisk.
- -target target_vdisk_id | target_vdisk_name
- (Required) Specifies the ID or name of the target VDisk.
- -name new_name_arg
- (Optional) Specifies the name to assign to the new mapping.
- -consistgrp consist_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.
- -copyrate rate
- (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.
- -incremental
- (Optional) Marks the FlashCopy mapping as an incremental copy. The default is nonincremental. Once set, this value cannot be changed.
- -cleanrate rate
- (Optional) Sets the cleaning rate for the mapping. The rate value can be 0 - 100. The default value is 50.
- -iogrp iogroup_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 VDisk, if a single target map, or the I/O group of the other FlashCopy mapping to which either the source or target VDisks belong.
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 VDisks must be specified on the mkfcmap command. The mkfcmap command fails if the source and target VDisks are not identical in size. Issue the svcinfo lsvdisk -bytes command to find the exact size of the source VDisk for which you want to create a target disk of the same size. The target VDisk that you specify cannot be a target VDisk 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 VDisks 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 VDisks are the target and source VDisks, 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.
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 VDisk. 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.
Table 1 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.
| 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 |
An invocation example
svctask mkfcmap -source 0 -target 2 -name mapone
The resulting output
FlashCopy Mapping, id [1], successfully created