Developers Guide

8 Understanding RAID with Dell SC Series Storage | 3104-CD-DS
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Standard track RAID level are tracks not allocated to Fast Track.
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Fast Track RAID level applies to HDDs with the Fast Track license; does not apply to SSDs.
RAID 5 is not preferred for arrays with 967 GB or larger HDDs. RAID 6 and RAID 10-DM offer significantly
higher levels of resiliency with very high capacity disks.
1.4 RAID levels and redundancy
A storage type is a pool of storage with a single data page size and a specified redundancy level. SC Series
arrays use storage types to logically group disks into tiers. In typical SC Series environments, a single storage
type has all tiers of disks assigned. By default, data is migrated between tiers and RAID levels in 2 MB blocks
(data pages). Data can be moved in smaller or larger blocks to meet specific application requirements.
Because Dell Enterprise Manager (now Dell Storage Manager), enables redundancy selection for the storage
type at the time of installation or addition of new disks, the RAID levels are automatically allocated according
to either single or dual redundancy settings.
Figure 1 shows a typical two-tier SC Series array with single redundancy configured in Tier 1 and dual
redundancy configured in Tier 3.
Enterprise Manager storage type displaying Tier 1 as single redundancy and Tier 3 as dual
redundancy.
Note: Fast indicates the Fast Track RAID levels while Standard indicates non-Fast Track RAID levels. Fast
Track is a licensed feature that improves performance by consolidating frequently accessed blocks of data to
the outer tracks.
1.5 Dual redundancy requirements
Redundancy requirements for each disk tier are based on the size of the disks in the tier. Dual redundancy
may be required by the array during an installation or change to a storage type redundancy. The rules