2.
Basic Functions
RAID Functions
The same size drives (2.5", 3.5") and the same kind of drives (SAS disks, Nearline SAS disks, SSDs, or
SEDs) must be used to configure a RAID group.
Figure 8 Example of a RAID Group
SAS
SAS
600GB
600GB
SAS disks and Nearline SAS disks can be installed together in the same group. Note that SAS
•
disks and Nearline SAS disks cannot be installed with SSDs or SEDs.
Use drives that have the same size, capacity, rotational speed (for disks), Advanced Format
•
support, interface speed (for SSDs), and drive enclosure transfer speed (for SSDs) to configure
RAID groups.
If a RAID group is configured with drives that have different capacities, all the drives in the
-
RAID group are recognized as having the same capacity as the drive with the smallest capaci-
ty in the RAID group and the rest of the capacity in the drives that have a larger capacity can-
not be used.
If a RAID group is configured with drives that have different rotational speeds, the perform-
-
ance of all of the drives in the RAID group is reduced to that of the drive with the lowest ro-
tational speed.
If a RAID group is configured with SSDs that have different interface speeds, the perform-
-
ance of all of the SSDs in the RAID group is reduced to that of the SSD with the lowest inter-
face speed.
3.5" SAS disks are handled as being the same size type as the drives for high-density drive
-
enclosures. For example, 3.5" Nearline SAS disks and Nearline SAS disks for high-density drive
enclosures can exist together in the same RAID group.
-
When a RAID group is configured with SSDs in both the high-density drive enclosure
(6Gbit/s), and the 3.5" type drive enclosure or the high-density drive enclosure (12Gbit/s), be-
cause the interface speed of the high-density drive enclosure (6Gbit/s) is 6Gbit/s, all of the
SSDs in the RAID group operate at 6Gbit/s.
•
For details on the RAID levels that can be configured with Nearline SAS disks that have 6TB or
more, refer to
Table 7
shows the recommended number of drives that configure a RAID group.
Table 7 Number of Drives to Configure and the Recommended Number of Drives per RAID Group
RAID level
RAID0
RAID1
RAID1+0
RAID5
RAID5+0
Fujitsu Storage ETERNUS DX100 S4/DX200 S4, ETERNUS DX100 S3/DX200 S3 Hybrid Storage Systems Design Guide (Basic)
SAS
SAS
600GB
600GB
RAID group 1
"Supported RAID" (page
Number of configu-
Recommended number of drives (*1)
ration drives
2 to 16
—
2
2(1D+1M)
4 to 32
4(2D+2M), 6(3D+3M), 8(4D+4M), 10(5D+5M)
3 to 16
3(2D+1P), 4(3D+1P), 5(4D+1P), 6(5D+1P)
6 to 32
3(2D+1P) ´ 2, 4(3D+1P) ´ 2, 5(4D+1P) ´ 2, 6(5D+1P) ´ 2
Copyright 2023 Fujitsu Limited
SAS
SSD
600GB
400GB
16).
25
SSD
SSD
SSD
400GB
400GB
400GB
RAID group 2
P3AM-7642-32ENZ0