Recommended RAID Group Configuration
In an ETERNUS AF, a controller enclosure is connected to drive enclosures with multiple paths.
•
For the ETERNUS AF250 S3
There are no restrictions on the installation locations of drives that configure a RAID group.
To improve reliability, the installation location of drives that configure a RAID group must be considered.
Data reliability can be improved by selecting configured drives that are distributed to controller enclosures and
drive enclosures when a RAID group is created.
For details on the recommended number of drives that configure a RAID group, refer to
•
For the ETERNUS AF650 S3
There are no restrictions on the installation locations of drives that configure a RAID group.
The ETERNUS AF has four groups of paths.
Data reliability can be improved by taking the path groups into consideration when distributing drives to
configure a RAID group.
Note
•
To create a RAID group manually, keep the recommended placement in mind for the configured drive
that is described here.
•
For details on the recommended number of drives that configure a RAID group, refer to
Caution
When selecting a RAID level such as RAID1 and RAID1+0 that configure mirroring within a RAID group,
reliability is improved by installing paired drives in different drive enclosures that belong to two or more
separate path groups.
■
Mirroring Configuration
RAID1+0(4D+4M) is used in the following examples to explain how drives are installed to configure a mirroring
RAID level.
The drive number is determined by the IDs (DE-ID and CE-ID) of the enclosure and the slot number in which the
drive is installed. Starting from the smallest drive number in the configuration, half of the drives are allocated
into one group and the remaining drives are allocated into the other group. Each drive in the different groups
are paired for mirroring.
Example 1: All drives are installed in a single enclosure
Figure 122
Drive Combination 1
DE#00
Mirroring
A
B
C
D
A'
B'
C'
D'
4. Hardware Configurations
Recommended RAID Group Configuration
180
Design Guide
Summary of Contents for ETERNUS AF S3 Series
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