10400328-001 02/2011
©2011 Overland Storage, Inc.
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Chapter 3
Storage Configuration
Note:
The SnapServer 110 is a single disk server that does not support RAID
configurations other than the default RAID 0. The SnapServer 210 is a two-disk
server that supports RAID 0 and RAID 1. Discussions in this chapter of RAID 5,
RAID 6, and RAID 10 configurations and global hot spares only apply to
SnapServers with four (4) or more drives. For more information about RAID
configurations for SnapServer 110 and 210, see the
User’s Guide for
SnapServers 110 and 210
on the User CD.
This section describes the default configurations of SnapServers with four (4) or more
drives and expansion arrays, how to change this configuration, how to add capacity to
the SnapServer by attaching one or more expansion arrays, and how to prepare the
server to store data.
After deploying your SnapServer storage system, you should provision and configure
the servers for optimal use in your network environment. The four sections in this
chapter provide guidelines and procedures for administrators who are implementing a
SnapServer on their network:
• Determining capacity
• Changing the default storage configuration
• Configuring email notification, task scheduling, and security
• Migrating data from a legacy server or workstation to a SnapServer
Determining Capacity
The factory default configuration reduces potential capacity in order to provide a high
degree of data protection and backup capability. By default, SnapServers with four (4)
to eight (8) disk drives are configured into a RAID 5 created during the manufacturing
process (SnapServer 110 and SnapServer 210 are configured as a 1- and 2-drive RAID
0, respectively). SnapServers with twelve (12) drives are configured into a RAID 6. In
a RAID 5 configuration, the capacity of one drive is used for data protection, reducing
the available capacity of the server by one drive. In a RAID 6 configuration, two drives
are used for data protection, so the capacity is reduced by two drives.
Approximately 20% of the default RAID is available for snapshot space and 80% of the
default RAID is assigned to the primary data volume.
For example, to calculate the capacity of a SnapServer 520 with 1 TB total capacity in
its default state, consider both the hardware and software configuration:
• The four 250 GB disk drives each provide 240 GB of formatted capacity.
• The four disks in a RAID 5 configuration net 720 GB of capacity for the RAID.
• The snapshot space is 20% of the space available on the RAID, reducing the space
on the RAID for the data volume by 144 GB.
