Dell PowerVault 221S Optimizing Dell SCSI Solutions - Page 4

A REFERENCE GUIDE FOR OPTIMIZING DELL™ SCSI SOLUTIONS VER A02 Understanding each of the storage components with respect to these attributes will help in making intelligent decisions to determine an optimal configuration for a given application. The paper presumes that the reader has a basic understanding of different levels of RAID and interconnects technologies - Parallel SCSI (SPI-4), PCI vs. PCI-X vs. PCI-e. This paper presents a study of all storage components, as identified earlier, against various storage applications and different operating environments; however, specific behavior of each of the storage applications and management functions is beyond the scope of this document. In this document we present storage solution from Parallel SCSI perspective, specifically for Dell's Direct Attached Storage (DAS) products. Other storage technologies such as SAS, SATA, or Fibre Channel, as well as topologies such as Network Attached Storage (NAS) or Storage Area Network (SAN) are outside the scope of this document. All storage applications referred to herein are treated independent of any specific host system or server. 2. Storage Applications and Components Identify customer usage model and needs In order to select the correct storage solution for any given situation, it is important to understand what the application and user requirements will be for that solution. A good starting point is to have an understanding of basic storage profiling considerations. • Table 2-1: Storage Profiling Considerations Characteristic Performance Storage Capacity Needs Storage Growth Rate Criticality Values Description • Bandwidth (MB per sec.) • I/O size (KB/MB) • I/O Profile (read/write and random/sequential access mix) Performance is the overall ability of the solution to read and write data to disk. The performance requirements are usually determined by the type of application being utilized. Different applications have different performance requirements. For example, a database or e-mail server has mostly random disk access operations while a streaming media server would have • Latency mostly sequential disk access. Storage capacity is the current amount of storage space required by the application and user data. For Gigabytes example, e-mail storage for 100 users would require much less storage capacity than an e-mail store for 1000 users. Percent increase per year Storage growth is the expected increase in the amount of capacity that will be required as usage of the server increases. This is usually measured in the expected number of users or clients accessing the server Low, Medium, High, Very High Criticality defines the impact to mission critical business needs if the storage is offline. This characteristic is important for choosing the right RAID level, and determining if clustering is needed. Picking a solution based on the application profile One of the most important factors to consider when selecting a storage solution is the type of application that will be utilizing the storage solution. This defines the overall purpose of PAGE 4 11/17/2005