Release Notes

Storage configuration
11 Dell EMC SC Series: Performance and Availability | 4024-BP-SC
2 Storage configuration
This section provides general recommendations for optimizing the SC Series array to meet your specific
needs.
2.1 Disk folders and volumes
In general, it is recommended to use a single disk folder in SC Series arrays because this reduces complexity
and increases flexibility. However, it may be appropriate to configure multiple disk folders in some cases:
• Running different workloads (such as video and database applications) with different I/O profiles
• Dedicating resources to meet specific performance goals (for example, using SSD drives for a high-
performance application and HDDs for file editing)
• Having separate resources for multi-tenancy (for example, LUNs with VDI user data)
2.2 Usable capacity
SC Series storage allows for multiple RAID types to exist on the same drives. Therefore, calculating the
usable capacity on a system is not an exact science because there are many factors to consider, the main
ones consisting of the following:
• Storage profiles
• Use of snapshots
• Length of time snapshots are kept
• Amount of data written between snapshots
Analyzing thousands of customers with RAID 10 and RAID 5 in tier 1, the usable capacity averages about
77% efficiency. To better understand how these affect capacity, discuss with your Dell EMC storage specialist
or business partner.
2.3 RAID protection
SC Series storage supports multiple levels of RAID-protection schemes to protect user data against drive
failure. Disks are associated by tiers and redundancy (for example, tier 1 single redundancy or tier 3 dual
redundancy). The redundancy choice defines the types of mirror or parity RAID used for those disks. Single
redundancy includes a single drive for protection, such as RAID 5 or RAID 10. Dual redundancy has two
drives for protection, such as RAID 6 or RAID 10 dual mirror (RAID 10 DM).
Choose the RAID type that best suits your needs for performance, protection, and cost:
• RAID 10 provides the highest level of performance from a given set of drive resources, with the
lowest CPU requirements. However, it is only 50% efficient in usable drive capacity.
• RAID 10 DM uses an additional disk as a mirror and provides better availability than RAID 10 and has
a usable capacity of 33%.
• RAID 5 provides the best usable capacity from a set of drive resources, but at lower overall
performance and availability than RAID 10. In terms of capacity, RAID 5-5 is 80% efficient and RAID
5-9 is 89% efficient.
• RAID 6 provides better availability than RAID 5 and better usable capacity than RAID 10 and RAID
10 DM, but has the lowest performance potential of the RAID types. RAID 6-6 is 67% efficient and
RAID 6-10 is 80% efficient.