Database Reference
In-Depth Information
Table 6.11 Array IOPS Required at Different RAID Levels to Achieve 5,000 SQL
IOPS
To calculate the number of disks required to meet the required IOPS of a workload, we
use the following formula:
Required Disks for Required RAID IOPS = Required Array IOPS / IOPS per Disk
Example RAID 5 Disks = 9500 Array IOPS / 210 IOPS per 15K Disk = 45 Disks
As Table 6.12 demonstrates, to achieve 5,000 SQL IOPS 70% read at RAID 5 on 15K
RPM disks requires 45 disks, whereas it only requires 31 disks at RAID 1, RAID 10, or
RAID DP—a saving of 14 disks. If the workload is only 30% read, then we would
require 74 15K RPM disks at RAID 5 and only 40 15K RPM disks at RAID 1, RAID
10, or RAID DP. This would be a saving of 34 disks to achieve the same performance.
This assumes each disk can achieve the high end of the IOPS for that device. The less
number of IOPS per disk, the more disks in total will be needed. In this example, we've
used the high-end IOPS of each disk for the calculations. Be sure to check with your
storage vendor on their recommendations for IOPS per disk when doing any
calculations.
Table 6.12 Min Disks Required at Different RAID Levels to Achieve 5,000 SQL IOPS
To achieve 5,000 IOPS at RAID 6 70% read on 7.2K RPM disks, we'd need 125 disks
 
 
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