B-8Adaptec Storage Manager Pro User’s GuideUnderstanding the Array Selection CriteriaTo help you choose an array type, use the criteria in the followingtable. Decide how important each criterion is to meeting your datamanagement and storage needs.Criteria Definition ExamplesRandom-readperformanceAbility to locate and readdata directly from a filewithout having to searchsequentially from thebeginning of the file.Databases, transactionprocessing programs,and operating systempage fileRandom-writeperformanceAbility to write data directlyto a file without having tosearch sequentially from thebeginning of the file.Databases, transactionprocessing programs,and operating systempage fileSequential-readperformanceAbility to read large numbersof consecutive data elements.Streaming videoprograms and backup/restore programsSequential-writeperformanceAbility to write largenumbers of consecutive dataelements.Streaming videoprograms and backup/restore programsFaulttoleranceAbility to recover from afailure of one or more driveswithout interrupting user orapplication access to data.Whenever data is moreimportant than the costof storing itExpansion Ability of the system toincrease the available storagecapacity for the operatingsystem’s file system.Most systems requireexpansion capabilitiesto meet growing datastorage needs.LoadbalancingAbility to spread I/O acrossdrives.All I/O-intensiveapplications benefitfrom load balancing.Cost perusable unit ofspaceAbility to use all space in anarray to store user data.(Unusable space includesparity in a RAID 5 set and theredundant half of a mirrorset.)N/A
