Administrator Guide

– RAID 5-5 (striped across 5 drives)

– RAID 5-9 (striped across 9 drives)

• Dual-redundant: Protects against the loss of any two drives. Disks larger than 900 GB should use dual redundancy, and in some

cases it is mandated. Dual-redundant tiers can contain any of the following types of RAID storage.

– RAID 10 Dual-Mirror (data is written simultaneously to three separate disks)

– RAID 6-6 (4 data segments, 2 parity segments for each stripe)

– RAID 6-10 (8 data segments, 2 parity segments for each stripe)

Redundancy Level Recommendations and Requirements

Disk size is used to determine the redundancy level used in Storage Center. If any disk in a tier surpasses a threshold size, a specific

redundancy level can be applied to the tier containing that disk.

The following tables describe HDD and SSD redundancy level recommendations and requirements for Storage Center 7.1

NOTE: These threshold are applied when Storage Center 7.0 is installed, then disks are added.

Table 2. HDD Redundancy Recommendations and Requirements

Disk Size Level of Redundancy That is Recommended or Required

Maximum 966GB No recommended redundancy level, no required redundancy

level

967GB up to a maximum 1.93TB Recommend dual redundancy for existing and new page pools

1.94TB and higher Required dual redundancy for new page pools

2.79TB and higher Required dual redundancy for existing page pools

Table 3. SSD Redundancy Recommendations and Requirements

Disk Size/Class Level of Redundancy That is Recommended or Enforced

Up to 1.7TB for WI and RI No recommended redundancy level, no required redundancy

level

1.8TB up to 3.9TB for WI and RI Recommend dual redundancy for existing and new page pools

4TB and higher for WI and RI Required dual redundancy for new page pools

Data Progression

Storage Center uses Data Progression to move data within a virtualized storage environment. Data Progression moves data

between tiers and drive types, as well as among multiple RAID levels within the same tier, for a constant balance of performance

and cost.

How Data Progression Works

Once every 24 hours, Storage Center assesses disk use and moves data to disk space that is more efficient for the data usage. By

default, Data Progression runs each day at 7 PM system time, but the timing of the run can be changed in the Storage Center

settings. Data Progression behavior is determined by the Storage Profile applied to each volume.

NOTE: With SCv2000 series controllers, Data Progression moves data between RAID types and restripes RAID, but does

not move data between storage tiers.

Data Progression and Snapshots

Storage Center also uses Data Progression to move snapshots. When a snapshot is created, either as scheduled or manually, the

data is frozen and moved to the tier specified by the Storage Profile to hold snapshots.

Storage Center Overview