19. September 2017 aerialsurveybase

RAID-3: Lack of write speed gain (Part 3)

Why there is no write speed gain when using a higher RAID level?

in Part 2 – Which RAID Level should I use? we talked about the different RAID levels, now the question is, which RAID level will be the perfect one for my application?

typical RAID Levels (commonly used) provide us with these fundamental rules:

Based on a disk array based on 8 drives (see sample here)

RAID 0 RAID 1 RAID 5 RAID 6 RAID 10
minimum disks: 2 2 3 4 4
Speed gain READ: 8x read Up to 8x read 7x read 6x read 8x read
Sped gain WRITE: 8x write no no no 4x write
use: High End Workstation, real-time applications OS, databases Data warehousing, web server, archiving High End Workstations, real-time applications, transitory data, archiving Fast databases, application servers
Data Protection: no protection Single-disk failure Single-disk failure Two-disk failure single disk failure in each sub-array
Capacity utilization of all disks: 100% 50% 66-94% 50-88% 50%

 

As we see, a write speed gain appears only when using a RAID 0, an increased write performance can be used with RAID 10 as well.

Write speed gain is a fundamental factor when handling intermediate data.

CrystalDiskMark Ramdisk to Single Drive

CrystalDiskMark Ramdisk to Single Drive

CrystalDiskMark Ramdisk to SSD

CrystalDiskMark Ramdisk to SSD

CrystalDiskMark Ramdisk to RAID0

CrystalDiskMark Ramdisk to RAID0

CrystalDiskMark Ramdisk to Storage Pool Storage Spaces RAID 5

CrystalDiskMark Ramdisk to Storage Pool/Storage Spaces RAID 5

CrystalDiskMark Ramdisk to JBOD

CrystalDiskMark Ramdisk to JBOD

CrystalDiskMark Ramdisk to RAMDISK

CrystalDiskMark Ramdisk to RAMDISK

Continue with Part 4 –  The Myth of Redundancy in Data Storage, where we will talk about the Question of Redundancy when using RAIDs.

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