Dell PowerVault MD3000i Hardware Owner's Manual

Also see for PowerVault MD3000i: Getting started Tuning guide System installation guide User guide Information update

Contents

Dell PowerVault MD3000i Hardware Owner's Manual Manual pdf 31 page image

Using Your RAID Enclosure 31Supported RAID LevelsRAID levels determine the way in which data is written to physical disks.Different RAID levels provide different levels of accessibility, redundancy, andcapacity.Using multiple physical disks has several advantages over using a singlephysical disk, including:• Placing data on multiple physical disks, called striping, means thatinput/output (I/O) operations can occur simultaneously and improveperformance.• Storing redundant data on multiple physical disks using mirroring or paritysupports reconstruction of lost data if an error occurs, even if that error isthe failure of a physical disk.Each RAID level provides different performance and protection. You shouldselect a RAID level based on the type of application, access, fault tolerance,and data you are storing.The storage array supports RAID levels 0, 1, 5, and 10.RAID 0RAID 0 uses disk striping to provide high data throughput, especially for largefiles in an environment that requires no data redundancy. RAID 0 breaks thedata down into segments and writes each segment to a separate physical disk.I/O performance is greatly improved by spreading the I/O load across manyphysical disks. Although it offers the best performance of any RAID level,RAID 0 lacks data redundancy (fault tolerance). Choose this option only fornon-critical data, because failure of just one physical disk will result in the lossof all data.RAID 1RAID 1 uses disk mirroring so that data written to one physical disk issimultaneously written to another physical disk. This is recommended forsmall databases or other applications that do not require large capacity.RAID 1 provides full data redundancy, meaning that if one disk fails, themirrored disk automatically maintains throughput with no data loss.