RVGSnapshot Agent
The RVGSnapshot agent automates the taking of space-optimized snapshots on a secondary RVG; since these snapshots can be mounted and written to without affecting the actual replicated data, a space-optimized snapshot can be an effective tool for scheduling a "fire drill" to confirm that a wide-area failover is possible. By combining this agent with VCS Mount agents and VCS agents that manage the application being replicated, a special fire drill service group can be created that can be onlined and offlined at regularly scheduled intervals to confirm the robustness of a disaster recovery environment.
In addition to the agent itself, a text-based wizard /opt/VRTSvcs/bin/fdsetup that prepares the VVR and VCS infrastructure for a fire drill and a script /opt/VRTSvcs/bin/fdsched that runs the fire drill and consolidates the results are included with this package. Complete details are in the VERITAS Cluster Server User's Guide.
The RVGSnapshot agent includes the following key features:
- Automates the process of creating a space-optimized snapshot on a VVR secondary that can be mounted to simulate a wide-area failover without affecting the production application.
- Includes a wizard to effectively set up and schedule fire drills that are completely managed by VCS.
While the fdsetup wizard configures the appropriate resources for a fire drill group, the following table summarizes the function of the RVGSnapshot agent, its entry points, state definitions, and attributes:
| Description
|
Creates and destroys a transactionally consistent space-optimized snapshot of all volumes in a VVR secondary replicated data set.
|
| Entry Points
|
online---Creates a transactionally consistent snapshot of all volumes in the RDS.
offline---Destroys the snapshot.
clean---Cleans up any failed snapshot creation or deletion.
monitor---No operation; failure of the snapshot will be indicated by the failure of the Mount resource of any filesystems mounted on it.
|
| Detecting Failure
|
The RVGSnapshot resource faults on timeout if a snapshot creation did not succeed during an online.
|
| State Definitions
|
ONLINE---Indicates that a snapshot was created.
OFFLINE---Indicates that a snapshot was destroyed.
|
| Required Attributes
|
Type and
Dimension
|
Definition
|
RvgResourceName
|
string-scalar
|
The name of the VCS RVG-type resource that manages the RVG that will be snapshot by this agent.
|
CacheObj
|
string-scalar
|
Name of the cache object that is required for a space-optimized snapshot; the fdsetup wizard will create one if it does not exist
|
Prefix
|
string-scalar
|
Token prepended to the name of the actual volume when creating the snapshotted volumes.
|
| Optional Attributes
|
Type and
Dimension
|
Definition
|
DestroyOnOffline
|
int-scalar
|
A flag to indicate whether to destroy the snapshot upon offlining the resources. For a fire drill, the snapshot should be deleted to reduce any performance impact of leaving the snapshot for a long period of time; however, if there is interest in keeping the data, then this value should be set to 0. The default is 1 (true).
|
FDFile
|
temporary string-scalar
|
The fire drill schedule updates this attribute with the system name and the path to a file containing the output of the last complete fire drill for the group containing an RVGSnapshot resource.
|
Type Definition
type RVGSnapshot (
static keylist RegList = { Prefix }
static int InfoTimeout = 0
static int NumThreads = 1
static str ArgList[] = { RvgResourceName, CacheObj, Prefix, DestroyOnOffline }
str RvgResourceName
str CacheObj
str Prefix
boolean DestroyOnOffline = 1
temp str FDFile
)
|
