Dell EqualLogic PS6210XS EqualLogic Group Manager Administrator s Guide PS Ser - Page 122

Enable and Disable a Volume RAID Preference, Prerequisites

Page 122 highlights

Table 29. 42-Drive Configuration shows the RAID set relationship for each RAID type in a 42-drive configuration. Table 29. 42-Drive Configuration RAID Policy Spare Disks RAID Set Relationship RAID 6 2 (12+2) (12+2) (10+2) RAID 10 2 (7+7) (7+7) (5+5) RAID 50 2 (12+2) (12+2) (10+2) RAID 5 2 (12+2) (12+2) (10+2) Best Practices Yes Yes Not for business-critical data Not for business-critical data Table 30. 48-Drive Configuration shows the RAID set relationship for each RAID type in a 48-drive configuration. Table 30. 48-Drive Configuration RAID Policy Spare Disks RAID Set Relationship RAID 6 1 (12+2, 12+2, 12+2) (3+2) RAID 10 2 (7+7, 7+7, 7+7) (2+2) RAID 50 2 (6+1 ,6+,1, 6+1, 6+1, 6+1, 6+1) (3+1) RAID 5 2 (12+1, 12+1, 12+1) (6+1) Best Practices Yes Yes For selected configurations Not for business-critical data Table 31. 84-Drive Configuration shows the RAID set relationship for each RAID type in a 84-drive configuration. Table 31. 84-Drive Configuration RAID Policy Spare Disks RAID Set Relationship RAID 6 2 (12+2) (12+2) (12+2) (12+2) (12+2) (10+2) RAID 6 Accelerated 1 HHD 1 SSD (12+2 HDD) (12+2 HDD) (12+2 HDD) (12+2 HDD) (10+2 HDD) (12+2 SSD) Best Practices Yes N/A RAID 10 2 RAID 50 2 RAID 5 2 (7+7) (7+7) (7+7) (7+7) (7+7) (6+6) (12+2) (12+2) (12+2) (12+2) (12+2) (10+2) (12+2) (12+2) (12+2) (12+2) (12+2) (10+2) Yes Not for business-critical data Not for business-critical data Enable and Disable a Volume RAID Preference A PS Series group uses automatic performance load balancing (enabled by default) to identify the RAID level that provides the best performance for a volume and store volume data on pool members with that RAID level, if such members are available. Prerequisites The following prerequisites and considerations apply: • RAID 5 does not offer optimal data protection for business-critical data due to the higher risks of encountering a second drive failure during a rebuild, and is therefore not recommended. You cannot configure RAID 5 using the Group Manager GUI; however, it can be configured using the CLI. • Thin clones inherit the RAID preference, if any, of the template volume. You cannot set a separate RAID preference for a thin clone. • You can override automatic performance load balancing by enabling a RAID level preference on a volume. • If you enable a RAID preference, the group attempts to store volume data on pool members with that RAID level. The group still uses capacity-based load balancing on the volume. 122 PS Series Group Operations

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Table 29. 42–Drive
Configuration
shows the RAID set relationship for each RAID type in a 42-drive
configuration.
Table 29. 42–Drive
Configuration
RAID Policy
Spare Disks
RAID Set Relationship
Best Practices
RAID 6
2
(12+2) (12+2) (10+2)
Yes
RAID 10
2
(7+7) (7+7) (5+5)
Yes
RAID 50
2
(12+2) (12+2) (10+2)
Not for business-critical data
RAID 5
2
(12+2) (12+2) (10+2)
Not for business-critical data
Table 30. 48-Drive
Configuration
shows the RAID set relationship for each RAID type in a 48-drive
configuration.
Table 30. 48-Drive
Configuration
RAID Policy
Spare Disks
RAID Set Relationship
Best Practices
RAID 6
1
(12+2, 12+2, 12+2) (3+2)
Yes
RAID 10
2
(7+7, 7+7, 7+7) (2+2)
Yes
RAID 50
2
(6+1 ,6+,1, 6+1, 6+1, 6+1, 6+1) (3+1)
For selected
configurations
RAID 5
2
(12+1, 12+1, 12+1) (6+1)
Not for business-critical data
Table 31. 84–Drive
Configuration
shows the RAID set relationship for each RAID type in a 84-drive
configuration.
Table 31. 84–Drive
Configuration
RAID Policy
Spare Disks
RAID Set Relationship
Best Practices
RAID 6
2
(12+2) (12+2) (12+2) (12+2) (12+2) (10+2)
Yes
RAID 6
Accelerated
1 HHD
1 SSD
(12+2 HDD) (12+2 HDD) (12+2 HDD)
(12+2 HDD) (10+2 HDD) (12+2 SSD)
N/A
RAID 10
2
(7+7) (7+7) (7+7) (7+7) (7+7) (6+6)
Yes
RAID 50
2
(12+2) (12+2) (12+2) (12+2) (12+2) (10+2)
Not for business-critical data
RAID 5
2
(12+2) (12+2) (12+2) (12+2) (12+2) (10+2)
Not for business-critical data
Enable and Disable a Volume RAID Preference
A PS Series group uses automatic performance load balancing (enabled by default) to identify the RAID level that provides the best
performance for a volume and store volume data on pool members with that RAID level, if such members are available.
Prerequisites
The following prerequisites and considerations apply:
RAID 5 does not
offer
optimal data protection for business-critical data due to the higher risks of encountering a second drive
failure during a rebuild, and is therefore not recommended. You cannot
configure
RAID 5 using the Group Manager GUI; however,
it can be
configured
using the CLI.
Thin clones inherit the RAID preference, if any, of the template volume. You cannot set a separate RAID preference for a thin
clone.
You can override automatic performance load balancing by enabling a RAID level preference on a volume.
If you enable a RAID preference, the group attempts to store volume data on pool members with that RAID level. The group still
uses capacity-based load balancing on the volume.
122
PS Series Group Operations