Unisphere and Unisphere Central 2020 R1 Administrator's Guide

Modify Tier Redundancy

Modify tier redundancy to change the redundancy level for each tier in a Storage Type. After modifying tier redundancy, a RAID rebalance is required to move data to the new RAID levels.

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 Storage Types.
   The Storage Types view is displayed.
3. In the Storage Type area, select the Storage Type to modify, then click (Edit).
   The Modify Tier Redundancy dialog box opens.
4. Modify the redundancy for each tier as needed.
   • Redundant: Protects against the loss of any one drive (if single redundant) or any two drives (if dual redundant).
   • Non-Redundant: Uses RAID 0 in all classes, in all tiers. Data is striped but provides no redundancy. If one drive fails, all data is lost.
     NOTE Non-Redundant is not recommended because data is not protected against a drive failure. Do not use non-redundant storage for a volume unless the data has been backed up elsewhere.
5. For Redundant Storage Types, you must select a redundancy level for each tier unless the drive type or size requires a specific redundancy level
   • 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.)
6. Drive Addition is selected by default. Leave this option selected.
7. Click OK.
   A RAID rebalance starts.