Hardware manual

Group Administration Group members

6–6

Table 6-1 compares the performance and availability characteristics of the supported RAID levels. The first

column lists workload requirements, with the other columns respectively listing the performance quality for each

requirement at RAID

10, RAID 50, RAID 5, and RAID 6.

Table 6-1: RAID Level Characteristic Comparison

Workload Requirement RAID10 RAID 50 RAID 5 RAID 6

Capacity Average Good Excellent Good

Availability Excellent Good Average Excellent

Sequential reads Excellent Excellent Excellent Excellent

Sequential writes Good Good Good Good

Random reads Excellent Excellent Excellent Excellent

Random writes Excellent Good Average Average

Performance impact of drive failure or

ID reconstru

ction

Minimal Moderate Moderate to heavy Heavy

Supported RAID policy conversions

While a member remains online, you can convert it from one RAID policy to another only if the new RAID policy

provides the same or more space than the current policy.

Table 6-2 shows the supported RAID policy conversions. The

first column lists RAID configurations, and the

second column lists supported RAID policy

conversions for them.

Table 6-2: Supported RAID Policy Conversions

Current RAID Policy Supported Conversion

RAID 10 All

RAID 10 no spares RAID-5, RAID-50, RAID-50 no spares, RAID-6, RAID6 no

ares

RAID 50 RAID-5, RAID-50 no spares, RAID-6, RAID6 no spares

RAID 50 no spares RAID-5,RAID-6, RAID6 no spares

RAID 5 None

RAID 6 RAID-5

RAID 6 no spares RAID-5

RAID 6 Accelerated None

If a RAID policy conversion is not supported, you can remove the member from the group and then add it to the

group again. You can then set the RAID policy.

Setting the RAID policy and pool for a new member

After you add a member to a PS Series group, you must set the RAID policy for the member and choose the storage

pool. The storage in the member is available after you set the RAID policy. See Member RAID policies.

Notes: If you used the Remote Setup Wizard to create a group and a

dd the first member to the group, you already

set the RAID policy for the member, and the group automatically assigned the member to the default pool.

If you want to use a no-spare disks RAID policy, you must use the Group Manager CLI to set the RAID

policy.