vxsnap


vxsnap
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The vxsnap CLI utility lets you perform multiple snapshots at the same time. To use vxsnap, you must have InfoScale Enterprise installed.

Note:

FlashSnap is available only with the Enterprise edition. See the "Licensing" section in the Veritas InfoScale Installation and Upgrade Guide for details.

Note:

Dynamic disks belonging to a Microsoft Disk Management Disk Group do not support the vxsnap command.

The vxsnap CLI utility makes use of both FlashSnap and Volume Shadow Copy Service (VSS) technology to create high-quality snapshots that can be done when application files are open. VSS can quiesce the application for the moment when the snapshot is created and then resume the application immediately after the snapshot; but a VSS-aware application must be used, such as Microsoft SQL Server. The vxsnap CLI utility acts as a VSS requestor, which lets you use SFW to initiate VSS snapshots at any time.

The vxsnap utility is designed to create and restore multiple snapshot sets.

The vxsnap CLI utility lets you name the snapshot volume. You must create the mirror for the volume before using the vxsnap CLI utility. The vxsnap prepare command can be used to create the mirror for the volume.

The vxsnap CLI utility allows a traditional full snapshot or a Microsoft Copy on Write (COW) snapshot. Microsoft COW snapshots have the benefit of being faster than full snapshots and take up less storage space.

A COW snapshot creates a shadow copy that is differential. When a change to the original volume occurs, the block that is about to be modified is read and then written to a "differences area", which preserves a copy of the data block before it is overwritten with the change. Thus making a copy of the block before it is changed. Using the blocks in the differences area and unchanged blocks in the original volume, a copy of the volume can be constructed that represents the volume in the state before any changes occurred.

The benefit of the COW snapshot is that it creates shadow copies very rapidly because it only writes the changed blocks at a given time. Using the blocks in the differences area and unchanged blocks in the original volume, the initial state of the original volume can be reconstructed.

Note:

Either the prepare or start keyword may be used in the CLI, however prepare is recommended.

Note:

For vxsnap examples , see the application-specific Solutions guide. For example, for Microsoft SQL Server, refer to the Storage Foundation and High Availability Solutions Quick Recovery and Microsoft Clustering Solutions Guide for Microsoft SQL.

Note:

To use vxsnap, the disk group must be a Storage Foundation for Windows 4.0 or later version. You must upgrade the disk groups that are created with an earlier version of Volume Manager for Windows before using the vxsnap utility.

Note:

The vxsnap commands must be invoked on a local system.

prepare

Creates snapshot mirrors of the volumes in the specified component. The snapshot mirrors remain attached to and synchronized with the original volumes

Note:

Either the prepare or start keyword may be used in the CLI, however prepare is recommended.

create

Creates simultaneous snapshots of all volumes in the specified component, providing a point-in-time snapshot set.

reattach

Reattaches and desynchronizes an existing snapshot set to the original database volumes.

restore

Restores a volume, database, or component from a snapshot set.

refresh

Refreshes all VSS Writers and component objects.

diffarea

Manages shadow storage area for COW snapshots. For example, the management of shadow storage area creation, size, and removal.

delete

Deletes COW snapshots corresponding to the information in the specified snapshot set.

Type the following sequence to view a description of the command syntax:

vxsnap <Keyword> -?

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