Table 110 Drive Characteristics - Fujitsu ETERNUS DX S5 Series Design Manual

6. Hardware Configurations
Installation Conditions and Installation Rules
- 3.5" Nearline SAS disks (8TB)
- 3.5" Nearline SAS disks (10TB)
- 3.5" Nearline SAS disks (12TB)
- 3.5" Nearline SAS disks (14TB)
- 3.5" Nearline SAS self encrypting disks (8TB)
- 3.5" Nearline SAS self encrypting disks (12TB)
• When using Advanced Format (512e) disks, make sure that Advanced Format (512e) is supported
by the server OS and the applications. If the server OS and applications do not support Advanced
Format (512e), random write performance may be reduced.
• For details on the RAID levels that can be configured with Nearline SAS disks that have 6TB or more,
refer to
●
SSDs
SSDs are reliable drives with high performance. SSDs are used to store high performance databases and
other frequently accessed data.
Flash memory as a storage media provides better random access performance than disks such as SAS disks
and Nearline SAS disks. Containing no motors or other moving parts, they are highly resistant to impact.
The ETERNUS DX supports SSDs that have a high level wear leveling function and sufficient reserved space.
Note that if the expected total write capacity is exceeded, the frequency of errors gradually increases, which
may lead to a reduction in the write performance. The ETERNUS DX has a function that shows the remaining
capacity as a percentage (health) in proportion to the expected total write capacity.
The number of rewrites may exceed the limit within the product warranty period if SSDs are used in a RAID1
configuration that has a high I/O access load.
The following types of SSDs are supported in the ETERNUS DX.
• SSDs (with a 12Gbit/s interface speed) that are compatible with Extreme Cache Pools
• Value SSDs (with a 12Gbit/s interface speed) that are incompatible with Extreme Cache Pools
Value SSDs are available at a lower cost per capacity than conventional SSDs by optimizing the guaranteed
write endurance and the reserved space.
When random access (especially with write access) continues for several hours, the performance of Value
SSDs may be reduced compared with SSDs that support Extreme Cache Pool.
Note that the product's actual capacity of a Value SSD differs from the capacity that is displayed in ETERNUS
Web GUI and ETERNUS CLI. For example, 2.00TB is displayed for a 1.92TB Value SSD.
The drive characteristics of SAS disks, Nearline SAS disks, and SSDs are shown below.
Table 110
Type
SAS disks
Nearline SAS Disks
SSDs
◎: Very good ¡: Good △: Reasonable
*1: Bits are used to compare the prices for each drive type and the price goes up in the following order: ◎ < ¡ < △.
"Supported RAID" (page 33).
Drive Characteristics
Reliability
¡
△
◎
Performance
¡
△
◎
290
Price (*1)
¡
◎
△
Design Guide