Detailed Information for RAID Levels, Drives, and Volumes

RAID Level

For "RAID Level", select the appropriate level according to the functions and purposes.

Features and Required Number of Drives for Each RAID Level

The following table shows the features and the required number of drives for each RAID level.

Actual RAID group configurations (or the number of available drives) vary depending on the maximum number of drives that can be installed in the storage system.

Display item	RAID level (*1)	Feature	Required number of drives (*2)
RAID1+0	High Performance (RAID1+0)	The high I/O performance of RAID0 (striping) is combined with the reliability of RAID1 (mirroring).	2D+2M - 16D+16M
RAID5	High Capacity (RAID5)	Data divided into units of blocks and parity information that is created from the data are allocated across multiple drives to allow data redundancy.	2D+1P - 15D+1P
RAID6	High Reliability (RAID6)	The use of double parity allows the full recovery of lost data even in the event that two of the drives fail.	3D+2P - 14D+2P
RAID6-FR	High Reliability (RAID6-FR)	Configure a single RAID group with multiple RAID redundant sets and reserved areas equivalent to a hot spare. Distributing data in RAID groups allows high-speed rebuilding when the first drive fails. A recovery can be performed with up to two drive failures, however when the second drive fails, the rebuild is operated at a normal speed. Several restrictions apply to the RAID groups and volumes of this RAID level. Refer to Restrictions for RAID6-FR for details.	(3D+2P)x2+1HS (4D+2P)x2+1HS (6D+2P)x2+1HS (9D+2P)x2+1HS (12D+2P)x2+1HS (5D+2P)x4+1HS (13D+2P)x2+1HS (8D+2P)x3+1HS (4D+2P)x5+1HS (3D+2P)x6+1HS
RAID5+0	Reliability (RAID5+0)	Prepare multiple RAID5 groups and configure them with striping according to the RAID0 method. For large capacity configurations, use of RAID5+0 instead of RAID5 results in enhanced performance, improved reliability, and shorter rebuilding times. Several restrictions apply to the RAID groups of this RAID level. Refer to Restrictions for RAID5+0 for details.	(2D+1P) × 2 - (15D+1P) × 2
RAID1	Mirroring (RAID1)	Data is mirrored to two drives (mirroring). If one drive fails, the other drive continues operation.	1D+1M
RAID0	Striping (RAID0)	Data is split in unit of blocks and stored across multiple drives (striping). RAID0 has no data redundancy.	2D - 16D

*1	:	The RAID levels in the table above, setting value fields, and display contents fields for descriptions are written according to how they actually appear in Web GUI. Other fields and descriptions in this manual use "RAIDxx" as an abbreviation for the RAID levels.
*2	:	D: Data drives, M: Mirror drives, P: Parity drives, HS: Hot Spares

Restrictions for RAID6-FR

The following restrictions apply to RAID groups (hereinafter referred to as "Fast Recovery RAID groups") that were created with RAID6-FR and volumes created in those RAID groups.

The following operations that use LDE cannot be performed for Fast Recovery RAID groups.
- Changing the RAID level to "RAID6-FR"
- Changing the RAID level from "RAID6-FR"
- Expanding the RAID group capacity by adding drives
"Standard (including concatenation volumes by means of LUN Concatenation)" and ODX Buffer volumes can be created in the Fast Recovery RAID group.
Encrypted volumes can be created in the Fast Recovery RAID groups. However, encrypting volumes that exist in Fast Recovery RAID groups is not allowed.
The Stripe Depth for a Fast Recovery RAID group is fixed at "64KB".
The Copybackless function is not performed when the first drive fails in a Fast Recovery RAID group. A high-speed rebuild is performed in a hot spare area within the RAID group, and when the failed drive is exchanged for a normal drive, copyback is performed.

Restrictions for RAID5+0

The following restrictions apply to RAID groups that are created with "RAID5+0".

The following operations that use LDE cannot be performed.
- Changing the RAID level to "RAID5+0"
- Changing the RAID level from "RAID5+0"
- Expanding the RAID group capacity by adding drives
The Stripe Depth for a new RAID group is fixed at "64KB".

About RAID0

RAID0 has no data redundancy. The use of RAID1+0, RAID5, RAID6, RAID6-FR, RAID5+0, or RAID1 is recommended.

About RAID Levels for Nearline/Nearline SEDs

For 6 TB or larger Nearline/Nearline SEDs, the configurable RAID levels are RAID0, RAID1, RAID6, and RAID-FR. Note that RAID0+1, RAID5, and RAID5+0 cannot be configured.

Drive Type

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

For information about the installed drives, refer to "Design Guide".

Drive Types

For SAS disks: "Online" or "Online/Nearline" (*1)
For Nearline SAS disks: "Nearline" or "Online/Nearline" (*1)
For SSDs: "SSD" or "NVMe"

*1

:

"Online/Nearline" is displayed if the volume type is WSV.

Note that "SED" is also displayed for self encrypting drives and "AF" is also displayed for Advanced Format compliant drives. (Example: Nearline SED AF)

Drive size

For 2.5-inch drives: 2.5"
For 3.5-inch drives: 3.5"

In some cases, the drive size is also displayed. (Example: 2.5" Nearline)

When Configuring RAID Groups or TPPs

If multiple drive types are used, 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.

Usage of Volumes

For volume "Usage", select the appropriate type according to the functions and purposes.

Display item	Usage	Description
Block	Block	The volumes that are used for the SAN.
Block/Dedupe&Comp	Block Deduplication and Compression Enabled	The Deduplication/Compression Volumes. The volumes that have both the Deduplication and Compression functions enabled.
Block/Dedupe	Block Deduplication Enabled	The Deduplication/Compression Volumes. The volumes that have the Deduplication function enabled.
Block/Comp	Block Compression Enabled	The Deduplication/Compression Volumes. The volumes that have the Compression function enabled.
System	VVOL Metadata	The system volumes that are used for storing the management information (metadata) of the Virtual Volume function. This volume is automatically created when the Virtual Volume function is set to "Enable" and when VVOL is created from ETERNUS SF Storage Cruiser for the first time.
System	Data Container (*1)	The Data Container Volumes. The container volumes that are used for the Deduplication/Compression function.
Migration	Migration	An External Volume that is used for data migrations.
Veeam	Veeam	The Veeam Snapshot Volumes that have both the Deduplication and Compression functions disabled.
Dedupe&Comp/Veeam	Dedupe&Comp/Veeam	The Veeam Snapshot Volumes that have both the Deduplication and Compression functions enabled.
Dedupe/Veeam	Dedupe/Veeam	The Veeam Snapshot Volumes that have the Deduplication function enabled.
Comp/Veeam	Comp/Veeam	The Veeam Snapshot Volumes that have the Compression function enabled.

*1

:

The volume is created automatically when Deduplication/Compression (or the Deduplication/Compression function) for TPP is enabled.

Usage of RAID Group

For RAID group "Usage", select the appropriate type depending on the functions and purposes.

Item	Description
Standard	A RAID group that is used for creating "Standard", "SDV", or "SDPV" type volumes
Standard / WSV	A RAID group that is used for creating the following volumes: "WSV" and "Standard" "WSV" and "SDV" "WSV" and "SDPV"
WSV	A RAID group that is used for creating "WSV" type volumes.
TPP	RAID groups that belong to TPPs.
FTRP	RAID groups that belong to FTRPs.
RDB	RAID groups that are registered as REC Disk Buffers.
Extreme Cache Pool	A RAID group that is registered as an Extreme Cache Pool.
Temporary	A RAID group that is temporarily created while LDE is being performed.
"-" (hyphen)	A RAID group that is not used.