Creating a Mapstore
A Mapstore is a virtual volume designated to hold state information and bitmaps for all snapshot sets, providing persistent storage. Mapstores ensure that enabled snapshot sets remain valid, without loss of snapshot data, when a storage server is stopped or restarted. Once a Mapstore is created, all snapshot sets (pre-existing or future) on that storage server will use the Mapstore. Part of the Mapstore functionality is to auto-enable snapshot sets at start up— this only applies to snapshot sets that were enabled at the time of the stop or shutdown. A Mapstore does not affect the performance of enabled snapshot sets. The use of Mapstore is optional, but highly recommended.
When you designate a virtual volume as a Mapstore, existing data on that virtual volume will be overwritten.
Use these guidelines when creating a Mapstore:
-
Must be on the same storage server as the snapshot set.
-
Create the Mapstore from a dynamic pool using the default size. Since dynamic pools are thin provisioned, the actual amount of store used will be the minimum required and will not exceed 256 GB.
-
Must be an unmapped virtual volume.
-
The Mapstore virtual volume must be dedicated to Mapstore use only. It cannot be the source or destination in a snapshot set or be used with AIM.
-
Can be from a Dual Path volume.
To create a Mapstore:
-
Open SANmanager and select the Snapshot tab.
-
Expand the SDS folder in the upper-left pane. Click on a storage server that is hosting snapshots. A list of available virtual volumes on that storage server appears in the upper-right pane.
-
Select the virtual volume to become a Mapstore and drag it from the upper-right pane to the Mapstore folder for that storage server in the lower-left pane. SANmanager designates the virtual volume as a Mapstore (see Snapshot column in upper-right pane), and it appears under the Mapstore folder.
-
Apply the configuration. Create a Mapstore for every storage server hosting snapshots.