Chapter 1 - Overview - Overland Storage Snapshot SnapSAN User Manual

Chapter 1
Snapshot is software for creating replication (snapshot image) at high speed and low cost on
a logical disk basis. For snapshot data, only the differential data in the replication source
logical disk is retained in storage. Therefore, you can maintain snapshot images with less
capacity than the replication source logical disk and use the replication volume at low cost.
Snapshot provides basic functions to extend online operation time and support 24-hour
operation for 365 days, such as processing data efficiently that increases day to day, and
performing online tasks and batch or backup processing in parallel that is performed during
the night.The snapshot function creates replication of a business volume (snapshot image)
and the function to control replication is installed in the disk array. A replication volume can
be created instantaneously at any time. Snapshot operations are executed from an
application server or an SnapSAN Manager client (Windows system). This chapter describes
the basics, such as an overview of snapshot, hardware configuration, and software
configuration.
Logical Fault and Physical Fault
A replication volume created by the snapshot function has the following features:
• It is a virtual volume holding only the differential data block with a copy-source
volume.
• It shares the data block other than the difference with a copy-source volume.
Therefore, the snapshot is affected differently depending on the fault type.
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Figure 1-1: Snapshot Overview
©2013 Overland Storage, Inc.
Overview
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