Performance Tuning
Striping Size Expansion
Striping Size Expansion is a function to expand the stripe depth value by specifying the stripe depth when creat-
ing a RAID group.
Expansion of the stripe size enables advanced performance tuning. For normal operations, the default value
does not need to be changed.
An expanded stripe depth reduces the number of drives that are accessed. A reduced number of commands to
drives improves the access performance of the corresponding RAID1+0 RAID groups. However, it should be noted
that an expanded stripe depth may reduce the sequential write performance for RAID5.
The stripe depth values that are available for each RAID type are shown below.
Table 37 Available Stripe Depth
RAID type Drive configuration (*1) Available stripe depth
Mirroring (RAID1) 1D+1M —
High performance (RAID1+0) All drive configurations 64KB, 128KB, 256KB, 512KB, and 1,024KB
Striping (RAID0)
High capacity (RAID5) 2D+1P – 4D+1P 64KB, 128KB, 256KB, and 512KB
5D+1P – 8D+1P 64KB, 128KB, and 256KB
9D+1P – 15D+1P 64KB and 128KB
Reliability (RAID5+0) All drive configurations 64KB
High reliability (RAID6)
High reliability (RAID6-FR)
*1: D: Data, M: Mirror, P: Parity
•
The read/write performance of the random access can be enhanced by changing the setting, however, note
that the performance can be degraded, depending on the used system.
•
The following restrictions are applied to the RAID groups with expanded stripe sizes:
-
Encryption and Logical Device Expansion cannot be performed on the volumes which belong to the RAID
group.
-
RAID groups with different stripe sizes configured cannot coexist in the same TPP or FTSP pools.
-
A WSV cannot be configured by concatenating RAID groups with different stripe sizes.
•
"Stripe Depth 512KB" cannot be specified for a "RAID5 (4D+1P)" configuration that is used for TPPs and
FTSPs.
•
"Stripe Depth 256KB" cannot be specified for a "RAID5 (8D+1P)" configuration that is used for TPPs and
FTSPs.
1. Function
Performance Tuning
101
FUJITSU Storage ETERNUS AF250 S2, ETERNUS AF250 All-Flash Arrays
Design Guide (Basic)
Copyright 2019 FUJITSU LIMITED
P3AG-1822-09ENZ0
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