Assign Dedicated Hot Spare

Overview

This function registers a drive as a Dedicated Hot Spare for a RAID group.

A Dedicated Hot Spare is a spare drive (hot spare) that is registered in the RAID group instead of the failed drive when a drive failure occurs. A Dedicated Hot Spare, unlike a Global Hot Spare, is used only for the specific RAID group.

If a drive fails, data copy (rebuild) to a Dedicated Hot Spare starts automatically.

If the Copybackless function is disabled and the failed drive is replaced with a normal drive, the data is copied back to the replacement drive. The Dedicated Hot Spare that is used instead of the failed drive then returns as a spare drive.

If the Copybackless function is enabled, the Hot Spare is registered in the RAID group after rebuilding and is used as a data drive. The failed drive in the RAID group is changed to a Dedicated Hot Spare after the rebuilding is complete. If the failed drive is replaced with a normal drive, the replacement drive can be used as a Dedicated Hot Spare.

Requirements for Hot Spares

Drives that are currently used cannot be registered as a hot spare.
- The drive status is "Present"
- The drives are not registered in RAID groups, TPPs, FTRPs, REC Disk Buffers, or Extreme Cache Pools
Make sure to register a hot spare with the same or a larger capacity than the data drives. If the hot spare capacity is smaller than the data drive, the drive does not work as the hot spare.
When a mix of Online disks, Nearline disks, SSDs, Online SEDs, Nearline SEDs, and SSD SEDs is installed together in the storage system, a hot spare of each type is required. Register the Dedicated Hot Spare with the same capacity as the maximum capacity drive for each type.
When multiple types of SSDs (SSD-H/SSD-M/SSD-L/SSD-H SED/SSD-M SED/SSD-L SED) are installed together in the storage system, a hot spare for each type is required. Register the hot spare with the same capacity as the maximum capacity SSD for each type.
Hot spares can be registered in any slots of the CEs and the DEs.

Caution

Only one RAID group can be registered for each Dedicated Hot Spare. A Dedicated Hot Spare cannot be registered to multiple RAID groups.
The Dedicated Hot Spares cannot be registered in the following RAID groups.
- RAID groups that belong to TPPs
- RAID groups that belong to FTSPs
- RAID groups that are registered as REC Disk Buffers
- RAID groups that are registered as Extreme Cache Pools

Note

When the failed drive and the Dedicated Hot Spare are switched, a Dedicated Hot Spare with the same capacity as the failed drive is used on a priority basis. If there is no Dedicated Hot Spare with the same capacity, a Dedicated Hot Spare with a larger capacity than the failed drive is used.
If the Dedicated Hot Spare is registered for a RAID group to which a failed drive belongs, the Dedicated Hot Spare is used before the Global Hot Spare. If there is no unused Dedicated Hot Spare and the drive fails, the Global Hot Spare is used.
To use the Copybackless function, the rebuild destination Hot Spare must satisfy some conditions. Refer to the [Setup Subsystem Parameters] function for details.

User Privileges

Availability of Executions in the Default Role

Default role	Availability of executions
Monitor
Admin
StorageAdmin
AccountAdmin
SecurityAdmin
Maintainer

Refer to "User Roles and Policies" for details on the policies and roles.

Settings

In this screen, select a RAID group in which the Dedicated Hot Spare is to be registered.

Assign Dedicated Hot Spare

Item

Description

Enclosure

The enclosure where the drive is installed is displayed.

CE: Controller Enclosure (2.5" and 3.5")

DE: Drive Enclosure (2.5", 3.5", and 3.5" high density DEs)

CE

CE#x

DE#yy

x: CE number

yy: DE number

Slot No.

The slot number of the enclosure where the drive is installed is displayed.

2.5" CE/DE: 0 - 23

3.5" CE/DE: 0 - 11

3.5" high density DE: 0 - 59

Drive Type

The drive type displayed for this item is a combination of the following.

Drive size
- For 2.5-inch drives: 2.5"
- For 3.5-inch drives: 3.5"
Drive type
- For SAS disks: Online
- For Nearline SAS disks: Nearline
- For SSDs, the following items are displayed depending on the SSD type.
  - For SSD-Hs (12 Gbit/s): SSD-H (*1)
  - For SSD-Ms (12 Gbit/s): SSD-M (*1)
  - For SSD-Ls (12 Gbit/s): SSD-L (*1)

Note that "SED" is also displayed for self encrypting drives and "AF" is also displayed for Advanced Format compliant drives.

*1

:

The displayed item varies depending on the interface speed (bandwidth) or the capacity of the reserved space. Unless otherwise specified, "SSD-H", "SSD-M", and "SSD-L" are collectively referred to as "SSD". In addition, there may be cases when "SSD SED" is used as the collective term for self encrypting SSD-Hs, SSD-Ms, and SSD-Ls.

Capacity

The capacity of the drive is displayed.

Speed

The drive speed is displayed.

For SSD or SSD SED, a "-" (hyphen) is displayed.

15000 rpm

10000 rpm

7200 rpm

Assign RAID Group

RAID groups in the following conditions are not displayed for the list of RAID groups in which the Dedicated Hot Spare can be registered:

RAID groups that cannot use the selected drive as a Dedicated Hot Spare (due to the drive capacity limit)
RAID groups that are registered as REC Disk Buffers
RAID groups that are registered as Extreme Cache Pools
RAID groups that are configured by drives that are a different type from the selected drive (note that RAID groups that are configured with "Online" disks and "Nearline" disks can be selected when the dedicated Hot Spare type is "Online" or "Nearline")
RAID groups that are temporarily created while LDE is being performed (RAID groups for which "Usage" is "Temporary")

Item	Description
Radio button	Select a RAID group in which the Dedicated Hot Spare is to be registered.
Name	The RAID group name is displayed.
Status	The RAID group status is displayed. Refer to "RAID Group Status" for details.
RAID Level	The RAID level is displayed. High Performance (RAID1+0) High Capacity (RAID5) High Reliability (RAID6) High Reliability (RAID6-FR) Reliability (RAID5+0) Mirroring (RAID1) Striping (RAID0)
Capacity	The total capacity of the RAID groups is displayed.
Drive Type	The drive type registered to the RAID group is displayed. If multiple drive types are used in the RAID group, the drive type is displayed as described below. If only "Online" type drives are used or if both "Online" and "Nearline" type drives are used, "Online" is displayed. If only "Online SED" type drives are used or if both "Online SED" and "Nearline SED" type drives are used, "Online SED" is displayed. If a single SSD type (SSD-H/SSD-M/SSD-L) is used or if multiple SSD types (SSD-H/SSD-M/SSD-L) are used, "SSD" is displayed. If a single SSD type (SSD-H SED/SSD-M SED/SSD-L SED) is used or if multiple SSD types (SSD-H SED/SSD-M SED/SSD-L SED) are used, "SSD SED" is displayed.
Minimum Drive Capacity	The drive with the smallest capacity in the RAID group is displayed.

Operating Procedures

Select a drive (multiple selections can be made) that is to be used as a Dedicated Hot Spare and click [Assign Dedicated HS] in [Action].
Note
- Select the same type of drives that configure the target RAID group. If multiple types of drives are selected, the [Assign Dedicated HS] is not available.
  
  If SSDs are used to configure the target RAID group, the type of SSD can be checked from the [RAID Group Detail] screen. Refer to the [RAID Group (Basic Information)] function for details.
Select which RAID group to use the selected drive as a Dedicated Hot Spare for and click the [Assign] button.

→ A confirmation screen appears.
Click the [OK] button.

→ Registration of the Dedicated Hot Spare starts.
Click the [Done] button to return to the [Drives] screen.