C H A P T E R 1

Array Overview

This chapter provides an overview of your Sun StorEdge 3120 SCSI array, which is an LVD/SE device. Topics covered in this chapter are:

Introducing the Array Model

Best Practices for the Sun StorEdge 3120 SCSI Array

Additional Software Tools

1.1 Introducing the Array Model

The Sun StorEdge 3120 SCSI array model is a JBOD (an array with disks and no controller). Providing up to 584-Gbyte RAID based on 146-Gbyte drives in a 1.75-inch tall by 19-inch wide storage unit, the Sun StorEdge 3120 SCSI array is a high-performance, storage device that contains up to four disk drives with SCSI connectivity to the data host.

FIGURE 1-1 Front View of a Sun StorEdge 3120 SCSI Array

Figure showing the Sun StorEdge 3120 SCSI array front bezel

The JBOD (Just a Bunch of Disks) array connects directly to a host server.

FIGURE 1-2 Rear View of a JBOD

Figure showing the rear view of a JBOD which includes redundant power supplies but does not have a controller.

Extensive reliability, availability, and serviceability (RAS) features include redundant components, notification of failed components, and the ability to replace components while the array is online.

The JBOD can be rackmounted in a server cabinet or expansion cabinet.

For information about specifications and agency approvals, see SCSI Array Specifications.

This document highlights SCSI best practices, which apply to the Sun StorEdge 3120 SCSI array.

1.2 Best Practices for the Sun StorEdge 3120 SCSI Array

The following sections outline small and large storage solutions for common entry-level server environments:

File

Application

These solutions can optimally use the Sun StorEdge 3120 SCSI array, a next-generation Ultra3 SCSI storage system designed to provide direct attached storage (DAS) to entry-level servers.

These solutions feature many performance features using familiar SCSI technology.

Entry-level servers are used for wide range of applications with distinct storage requirements, so the Sun StorEdge 3120 SCSI array features a modular architecture with flexible configurations. Modularity and flexibility enable the storage solution to quickly and easily adapt to a particular environment.

1.2.1 Entry-level Server Storage Requirements

Print, file, and application services are essential network requirements and are among the most popular uses of entry-level servers. The servers used to provide these functions are generally very inexpensive, highly compact units that are often installed in racks for convenience.

One example of such a server is the Sun Fire V120, an expandable single-processor server that occupies just 1 unit (1U) of rack space. Network servers are often distributed throughout an enterprise, making the Sun StorEdge 3120 SCSI array ideally suited for these applications due to its cost-effective direct attached storage design.


	Print Server	File Server	Application Server
Availability	Medium	Medium to high	Medium to high
Storage capacity	Low	Low to high	Low to medium
Special needs	High data rates and low cost	High data and transaction rates	Low cost and high transaction rates
Access pattern	Sequential	Sequential	Random

1.2.2 Print Server Architecture and Configuration

The following section outlines small and large storage solutions for print server environments. FIGURE 1-3 shows the scalability between the print server and the Sun StorEdge 3120 SCSI array.

FIGURE 1-3 Optimized Architecture for Print Servers

Figure showing optimized architecture for print servers.

TABLE 1-2 describes the possible print server configurations.


	Small Configuration	Large Configuration
JBOD Enclosures	1	1
Number of Disks	2	4
Bus Configuration	Dual-bus	Dual-bus
RAID Levels Used	Host-based RAID 1	Host-based RAID 1
Drive Configuration	1 LUN	2 LUNs

1.2.2.1 Tips and Techniques

Consider the following tips and techniques when configuring print servers.

Using a server's built-in SCSI port (if compatible) to minimize cost will result in satisfactory print server performance in most environments, even if the SCSI port does not operate at full Ultra320 speeds.

Data protection should be provided by host-based software volume management software using the operating system's volume manager or a third-party volume manager. The recommended configurations provide RAS similar to a single controller RAID array.

Each server must be connected to a different SCSI bus when using the large recommended configuration.

1.2.3 File Server Architecture and Configuration

The following section outlines small and large storage solutions for file server environments. FIGURE 1-4 shows the scalability between the file server and the Sun StorEdge 3120 SCSI array.

FIGURE 1-4 Optimized Architecture for File Servers

Figure showing optimized architecture for file servers.

TABLE 1-3 describes the possible file server configurations.


	Small Configuration	Large Configuration
JBOD Enclosures	1	1
Number of Disks	2	4
Bus Configuration	Single-bus	Dual-bus
RAID Levels Used	Host-based RAID 1	Host-based RAID 1
Drive Configuration	1 LUN	2 LUNs

Consider the following tips and techniques when configuring file servers.

You can use an Ultra3 SCSI port to connect the RAID array whenever the server is connected to a LAN using Gigabit Ethernet. Otherwise, a slower SCSI connection may create a performance bottleneck on the SCSI connection.

If the server has room for only one host adapter and you must choose between Ultra320 SCSI or Gigabit Ethernet adapters, install the Gigabit Ethernet host adapter and use the server's built-in SCSI port to provide the most benefit to users. However, this reduces the I/O to a slower SCSI speed.

Rapidly growing network response times as users are added is an indication the file server is limiting performance. If this occurs, examine the utilization of server memory, processors, and network adapters and expand those with the highest usage.

1.2.4 Application Server Architecture and Configuration

The following section outlines small and large storage solutions for application server environments. FIGURE 1-5 shows the scalability between the application server and the Sun StorEdge 3120 SCSI array.

FIGURE 1-5 Optimized Architecture for Application Servers

Figure showing optimized architecture for application servers.

TABLE 1-4 describes the possible application server configurations.


	Small Configuration	Large Configuration
JBOD Enclosures	1	1
Number of Disks	2	4
Bus Configuration	Dual-bus	Dual-bus
RAID Levels Used	Host-based RAID 1	Host-based RAID 1
Drive Configuration	1 LUN	2 LUNs

Consider the following tips and techniques when configuring application servers.

A single array providing storage for two servers reduces storage costs with little to no effect on application performance.

Use the built-in SCSI ports of application servers to further minimize costs rather than adding a host adapter, particularly when not using Gigabit Ethernet to the LAN.

Enhance application server availability by booting them from the RAID array rather than their internal drives. This also facilitates the rapid replacement of malfunctioning or failed servers.

1.3 Additional Software Tools

Additional software tools are available on the Sun Download Center located at:

http://wwws.sun.com/software/download/

The following software tools are available:

Sun StorEdge Configuration Service, a management and monitoring program

Sun StorEdge Diagnostic Reporter software, a monitoring utility

Sun StorEdge CLI, a command-line utility to manage the array

For details on using the software management tools with the SCSI array, see Software Management Tools.

For other supported software tools, refer to the release notes for your array, located at:

http://www.sun.com/products-n-solutions/hardware/docs/Network_Storage_Solutions/Workgroup/3120