Overland Storage Reviewing REO 9000 Concepts Requirements, Important Concepts to Understand

1

CHAPTER

Reviewing REO 9000 Concepts

and Requirements

The main steps involved in preparing to set up the REO Appliance include:

Step 1 Understanding the concepts of iSCSI, Fibre Channel (FC), disk-to-disk- to-tape (D2D2T) backup, redundant array of independent disks (RAID), tape emulation, logical volume management (LVM), and how the REO Appliance fits into the picture.

Step 2 Reviewing the requirements that your servers and network must meet to ensure successful installation and operation of the REO Appliance.

Important Concepts to Understand

To understand the configuration of the backup network and how it fits into the local-area network (LAN) or Fibre Channel (FC) storage-area network (SAN), review the following sections.

Internet SCSI (iSCSI) Protocol

Internet SCSI (iSCSI) is a standard protocol for universal access to shared storage devices over standard, Ethernet-based transmission control protocol/Internet protocol (TCP/IP) networks. The connection- oriented protocol transports SCSI commands, data, and status across an IP network. For more information, see Glossary and Acronym List on page 163.

iSCSI Architecture

The iSCSI architecture is based on a client-server model. The client is a host system that issues requests to read or write data. iSCSI refers to a client as an initiator. The server is a resource that receives and executes client requests. iSCSI refers to a server as a target.

File servers, which store the programs and data files shared by users, normally play the role of server. With the REO Appliance, the application and backup servers within your network act as clients or initiators and the REO Appliance acts as a server or target. The initiators can either be software drivers or iSCSI host bus adapters (HBAs) on the server that is being backed up.

Reviewing REO 9000 Concepts and Requirements W 11