Hot Spare Types; Number Of Hot Spares For Installation; Table 4.8 Recommended Number Of Hot Spares For Each Drive Type - Fujitsu ETERNUS DX80 S2 Overview

Chapter 4 System Configuration
4.5 Hot Spares
4.5.1

Hot Spare Types

Two types of hot spares are available:
• Global Hot Spare
This is available for any RAID group. When multiple hot spares are installed, the most appropriate drive is
automatically selected and incorporated into a RAID group.
• Dedicated Hot Spare
This is only available to a specified RAID group.
Assign "Dedicated Hot Spares" to RAID groups that contain important data, in order to preferentially improve
their access to hot spares.
4.5.2

Number of Hot Spares for Installation

The number of required hot spares is determined by the total number of drives.
The following table shows the recommended number of hot spares for each drive type.
Table 4.8 Recommended number of hot spares for each drive type
Model
ETERNUS DX80 S2
ETERNUS DX90 S2
Register hot spares to ensure steady operation of the ETERNUS DX Disk storage system. If a free hot spare is
available and one of the RAID group drives has a problem, data of this drive is automatically replicated in the
hot spare.
If a combination of SAS disks, Nearline SAS disks, SSDs, and SEDs is installed in the ETERNUS DX Disk storage
system, each different type of drive requires a corresponding hot spare.
There are two types of SSDs; SLC type SSDs and MLC type SSDs. Sorting by drive type is not necessary.
There are two types of SAS disks; 10,000rpm type SAS disks and 15,000rpm type SAS disks. If a drive error
occurs and a hot spare is configured in a RAID group with different speed drives, the performance of all the
drives in the RAID group is determined by the drive with the slowest speed.
When using SAS disks with different speeds, prepare hot spares that correspond to the different speed drives if
required.
The capacity of each hot spare must be equal to the largest capacity of the same-type drives.
Total number of drives
up to 120
1
1
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ETERNUS DX80 S2/DX90 S2 Disk storage system Overview
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up to 240
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2
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