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Comparison of snapshot features

Comparison of snapshot features for supported snapshot types compares the features of the various types of snapshots that are supported in VxVM.

Comparison of snapshot features for supported snapshot types

Snapshot feature

Full-sized instant (vxsnap)

Space-optimized instant (vxsnap)

Break-off
(vxassist or vxsnap)

Immediately available for use on creation

Yes 

Yes 

No 

Requires less storage space than original volume

No 

Yes 

No 

Can be reattached to original volume

Yes 

No 

Yes 

Can be used to restore contents of original volume

Yes 

Yes 

Yes 

Can quickly be refreshed without being reattached

Yes 

Yes 

No 

Snapshot hierarchy can be split

Yes 

No 

No 

Can be moved into separate disk group from original volume

Yes 

No 

Yes 

Can be turned into an independent volume

Yes 

No 

Yes 

FastResync ability persists across system reboots or cluster restarts

Yes 

Yes 

Yes 

Synchronization can be controlled

Yes 

No 

No 

Full-sized instant snapshots are easier to configure and offer more flexibility of use than do traditional third-mirror break-off snapshots. For preference, new volumes should be configured to use snapshots that have been created using the vxsnap command rather than using the vxassist command. Legacy volumes can also be reconfigured to use vxsnap snapshots, but this requires rewriting of administration scripts that assume the vxassist snapshot model.

If storage space is at a premium, space-optimized instant snapshots can be configured with some reduction of supported functionality. For example, space-optimized snapshots cannot be turned into independent volumes, nor can they be moved into a separate disk group for off-host processing.