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Using RAID 5 With Your Mac
Store your data on a fault-tolerant RAID 5 array
By Tom Nelson Tom Nelson Writer Tom Nelson is an engineer, programmer, network manager, and computer network and systems designer who has written for Other World Computing,and others. Tom is also president of Coyote Moon, Inc., a Macintosh and Windows consulting firm. lifewire's editorial guidelines Updated on December 2, 2020 Tweet Share Email Tweet Share Email Apple Macs iPad An RAID array is a storage solution that combines multiple hard drives into one unit for the purpose of storing, backing up, and providing redundancy and security. RAID 5, with disk striping and parity, is ideal for use as a file-storage server or application server. This choice for Mac users requires a minimum of three drives and provides fault tolerance and good performance. Mienny Getty Images A redundant array of independent disks (RAID) protects against the failure of a single drive and provides improved performance and fast transfer rates by storing data across multiple disks. Information in this article applies to RAID 5 with a Mac running macOS Catalina (10.15) through macOS Sierra (10.12). RAID Features
There are several RAID levels including RAID 0, RAID 1, RAID 3, RAID 5, RAID 6, and RAID 10. Each RAID category possesses one or more of these features: Disk striping refers to dividing data into blocks and writing the blocks across several storage devices.Disk mirroring refers to duplicating data on two or more disks.Parity bit calculates the data in two drives and stores the results on a third drive for the purpose of providing fault tolerance. RAID 5 is a cost-effective option that provides excellent performance and redundancy in high-read environments. About RAID 5 and the Mac
RAID 5 is a striping RAID level designed to increase the speed of disk reads and writes. Many Mac users opt for RAID 5 for multimedia file storage. Its read speed is fast, and the write speed is only slightly slower, due to the need to calculate and distribute the parity. RAID 5 excels at storing large files, where data is read sequentially. Smaller, randomly accessed files have mediocre read performance, and write performance can be poor due to the need to recalculate and rewrite the parity data for each write operation. Although RAID 5 can be implemented with mixed disk sizes, that isn't considered the preferred approach since the RAID 5 array size is defined by the smallest disk in the set. Calculating RAID 5 Array Size
RAID 5 arrays use the equivalent of a drive for storing parity, which means the overall array size can be calculated using the formula: S=d*(n-1) The d is the smallest disk size in the array, and n is the number of disks that make up the array. How RAID 5 Works
RAID 5 is similar to RAID 3 in that it uses a parity bit to ensure data integrity. However, unlike RAID 3, which uses a disk dedicated to storing the parity, RAID 5 distributes the parity to all drives in the array. RAID 5 provides for drive failure tolerance, allowing any single drive in the array to fail without losing any data in the array. When a drive fails, the RAID 5 array can still be used to read or write data. After the failed drive is replaced, the RAID 5 array enters a data recovery mode, in which the parity data in the array is used to rebuild the missing data on the newly installed drive. Software-Based vs Hardware-Based Controllers
Due to the need to perform parity calculations and distribute the resulting calculation, RAID 5 is at its best when operating in a hardware-based RAID enclosure. There are two types of RAID array controllers: hardware and software. Software-based controllers cost less and give the user flexibility when configuring the drives. Hardware-based controllers cost more but are recommended for complex arrays. The Disk Utility app included with Macs doesn't support creating software-based RAID 5 arrays. However, SoftRAID, from third-party developer SoftRAID, Inc., can be used if a software-based solution is needed. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire Software vs. Hardware Based RAID for External Drive Disk Utility Can Create a JBOD RAID Set for Your Mac How to Use Disk Utility in macOS 3 Best Free Full Disk Encryption Programs What Is RAID 10, and Does My Mac Support It? What Is a Data Sanitization Method? (Data Wipe Methods) Use Disk Utility to Create a RAID 1 (Mirror) Array What Is Seek Time? (Definition of an HDD's Seek Time) The 8 Best 8TB External Hard Drives of 2022 8 Things to Consider Before Buying a Desktop PC What Is a Hard Disk Drive? Use Disk Utility to Create a RAID 0 (Striped) Array Task Manager (What It Is & How to Use It) macOS Disk Utility Can Create Four Popular RAID Arrays How to Use the Format Command to Write Zeros to a Hard Drive Use Terminal to Create a RAID 0 (Striped) Array in OS X Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies