Administrator Guide

7. To modify the tier redundancy, select the Create Storage Type checkbox and then modify the redundancy for each tier as needed.
• Single Redundant: Single-redundant tiers can contain any of the following types of RAID storage:
• RAID 10 (each drive is mirrored)
• RAID 5-5 (striped across 5 drives)
• RAID 5-9 (striped across 9 drives)
• Dual redundant: Dual redundant is the recommended redundancy level for all tiers. It is enforced for 3 TB HDDs and higher and
for 18 TB SSDs and higher. Dual-redundant tiers can contain any of the following types of RAID storage:
• RAID 10 Dual-Mirror (data is written simultaneously to three separate drives)
• RAID 6-6 (4 data segments, 2 parity segments for each stripe)
• RAID 6-10 (8 data segments, 2 parity segments for each stripe.)
8. Click OK.
Managing Data Redundancy
Manage data redundancy by modifying tier redundancy or creating Storage Types.
Redundancy Requirements
Drive size is used to determine the redundancy level to apply to a tier of drives. If any drive in a tier surpasses a threshold size, a specific
redundancy level can be applied to the tier containing that drive. If a redundancy level is required, the Storage Center operating system
sets the level and it cannot be changed.
Table 7. HDD Redundancy Recommendations and Requirements
Disk Size Level of Redundancy Recommended or Enforced
Up to 3 TB Dual redundant is the recommended level
NOTE: Non-redundant storage is not an option for SCv2000 Series storage systems.
3 TB and higher Dual redundant is required and enforced
Table 8. SSD Redundancy Recommendations and Requirements
Disk Size Level of Redundancy Recommended or Enforced
Up to 18 TB Dual redundant is the recommended level
NOTE: Non-redundant storage is not an option for SCv2000 Series storage systems.
18 TB and higher Dual redundant is required and enforced
Managing RAID
Modifying tier redundancy, or adding or removing disks can cause data to be unevenly distributed across disks. A RAID rebalance
redistributes data over disks in a disk folder.
Rebalance RAID
Rebalancing RAID redistributes data over the disks according to the Storage Type. Rebalance the RAID after releasing a disk from a disk
folder, when a disk fails, or after adding a disk.
Steps
1. If you are connected to a Data Collector, select a Storage Center from the drop-down list in the left navigation pane of Unisphere
Central.
2.
From the
STORAGE menu, click Disks.
The Disks view is displayed.
3. Click Rebalance RAID.
The RAID Rebalance dialog box opens. If a RAID rebalance is needed, the dialog box shows RAID rebalance options.
Storage Center Maintenance
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