Viewing the FlashCopy mappings used by a VDisk

Use the FlashCopy® mappings Used by a VDisk panel in the SAN Volume Controller Console to display details about a selected FlashCopy mapping associated with the selected virtual disk (VDisk).

Attributes

Select
Allows you to select the FlashCopy mapping to use to perform an action from the task list.
Note: Only one row can be selected at a time.
Name
Displays the name of the FlashCopy mapping.
State
Displays the current state of the FlashCopy mapping. The following values are possible:
Idle or Copied
Indicates that the source and target VDisks act as independent VDisks even if a FlashCopy mapping exists between the two. Read and write caching is enabled for both the source and the target.
Preparing
Indicates that any changed write data for the source VDisk is flushed from the cache. Any read or write data for the target VDisk is discarded from the cache.
Prepared
Indicates that the mapping is ready to be started. While in this state, the target VDisk is offline.
Copying
Indicates that the copy is in progress.
Stopping
Indicates that the copy is in stopping.
Stopped
Indicates that the mapping has been stopped because either you issued a command or an input/output (I/O) error occurred. The copy can be restarted by preparing and starting the mapping again.
Suspended
Indicates that the copy bitmap is unavailable. The copying resumes when the bitmap recovers.
Source VDisk
Displays the name of the source virtual disk in this FlashCopy mapping.
Target VDisk
Displays the name of the target virtual disk in this FlashCopy mapping.
FC Group
Displays the name of the FlashCopy consistency group that contains this FlashCopy mapping.
Progress (%)
Displays the progress of the copy operation shown as a completion percentage 0% - 100%.
Cleaning Progress (%)
Displays the progress of the FlashCopy mapping cleaning operation if one is in process. The value is shown as a completion percentage of 0% - 100%. The cleaning process must complete before the FlashCopy mapping moves to the stopping state.
Copy Rate
Displays the copy rate for this mapping. The value selected can be the number 1 - 100 to indicate the copy rate (a higher number indicates a faster copy rate) or NOCOPY, which disables the copy process.

The following table shows the relationship of the copy and cleaning rate value 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

The data copied per second and the grains per second numbers represent standards that the SAN Volume Controller tries to achieve. The SAN Volume Controller is unable to achieve these standards if insufficient bandwidth is available from the nodes to the physical disks that make up the managed disks (MDisks) after taking into account the requirements of foreground I/O. If this situation occurs, background copy I/O contends for resources on an equal basis with I/O that arrives from hosts. Both tend to see an increase in latency and consequential reduction in throughput with respect to the situation had the bandwidth not been limited.

Automatically Delete
Displays whether a FlashCopy mapping will be deleted when it is done copying. The following values are possible:
Enabled
Indicates the cluster supports the automatic deletion of FlashCopy mapping when it is done copying.
Disabled
Indicates the cluster supports the automatic deletion of FlashCopy mapping when it is done copying; however, the function is turned off.
Not Supported
Indicates that the cluster does not have the capability to support the automatic deletion of FlashCopy mapping.
Incremental
Displays whether this FlashCopy is incremental. The following values are possible:
Yes
Indicates that only data changed since the last FlashCopy process on the source and target VDisk will be copied.
No
Indicates that the entire VDisk will be copied during a FlashCopy process.

Actions

You can initiate the following actions from this panel:
  • Create a Mapping
  • Modify a Mapping
  • Delete a Mapping
  • Prepare a Mapping
  • Start a Mapping
  • Stop a Mapping
  • View FC Mappings in Dependency Order
Go
Click this button after selecting a task from the task list. Clicking Go launches the panel for the task that you selected.
Refresh
Click this button to refresh the table with changed values.
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