Dell PowerVault MD3420 - Manual (Page 161)

successfully for all of the consistency group members, the operation fails and has no affect (that is, new
snapshot images are not created).
Based on this behavior all members for a consistency group usually have the same number of PiTs.
However, when a new member is added to a consistency group, that new member lacks the snapshot
images that were previously created on the established members of the consistency group. This is not
considered an error condition. Ensuing requests for deletion or rollback of snapshot images that only
exist on a subset of the consistency group members will only affect the members for which the specified
snapshot images actually exists.
For more information on scheduling snapshot images in a consistency group, see
Scheduling Snapshots .
Create Consistency Group Snapshot Image
Description
This command creates a new snapshot image for each base virtual disk that is a member of a snapshot
consistency group.
Syntax
create cgSnapImage consistencyGroup="consistencyGroupName"
Parameter
Parameter Description
consistencyGroup The name of the consistency group for which you
are creating snapshot images. Enclose the
consistency group name in double quotation
marks (" ").
Notes
You can use any combination of alphanumeric characters, hyphens, and underscores for the names.
Names can have a maximum of 30 characters.
The command causes all pending I/O operations to each base virtual disk that is a member of the
consistency group to be drained and suspended before creating the snapshot images. If the creation of
all of the snapshot images cannot be completed successfully for all of the consistency group members,
the operation fails and new snapshot images are not created.
Normally, all members of a snapshot consistency group will have the same number of snapshot images.
When you add a new member to a snapshot consistency group, that new member lacks the snapshot
images that were previously created on the established members of the snapshot consistency group. This
is not an error condition. Requests for deletion or rollback of snapshot images that exist on only a subset
of the snapshot consistency group members affects only those members for which the specified
snapshot image actually exists.
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