Raid 0; Raid 1; Raid 10; Raid 6 - Dell PowerVault MD3260i Administrator's Manual

• Number of physical disks in the disk array
• Capacity of the physical disks in the disk array
• Need for redundant access to the data (fault tolerance)
• Disk performance requirements

RAID 0

CAUTION: Do not attempt to create virtual disk groups exceeding 120 physical disks in a RAID 0 configuration even
if premium feature is activated on your storage array. Exceeding the 120-physical disk limit may cause your storage
array to be unstable.
RAID 0 uses disk striping to provide high data throughput, especially for large files in an environment that requires no
data redundancy. RAID 0 breaks the data down into segments and writes each segment to a separate physical disk. I/O
performance is greatly improved by spreading the I/O load across many physical disks. Although it offers the best
performance of any RAID level, RAID 0 lacks data redundancy. Choose this option only for non-critical data, because
failure of one physical disk results in the loss of all data. Examples of RAID 0 applications include video editing, image
editing, prepress applications, or any application that requires high bandwidth.

RAID 1

RAID 1 uses disk mirroring so that data written to one physical disk is simultaneously written to another physical disk.
RAID 1 offers fast performance and the best data availability, but also the highest disk overhead. RAID 1 is
recommended for small databases or other applications that do not require large capacity. For example, accounting,
payroll, or financial applications. RAID 1 provides full data redundancy.
RAID 5
RAID 5 uses parity and striping data across all physical disks (distributed parity) to provide high data throughput and
data redundancy, especially for small random access. RAID 5 is a versatile RAID level and is suited for multi-user
environments where typical I/O size is small and there is a high proportion of read activity such as file, application,
database, web, e-mail, news, and intranet servers.

RAID 6

RAID 6 is similar to RAID 5 but provides an additional parity disk for better redundancy. RAID 6 is the most versatile RAID
level and is suited for multi-user environments where typical I/O size is small and there is a high proportion of read
activity. RAID 6 is recommended when large size physical disks are used or large number of physical disks are used in a
disk group.

RAID 10

CAUTION: Do not attempt to create virtual disk groups exceeding 120 physical disks in a RAID 10 configuration
even if premium feature is activated on your storage array. Exceeding the 120-physical disk limit may cause your
storage array to be unstable.
RAID 10, a combination of RAID 1 and RAID 0, uses disk striping across mirrored disks. It provides high data throughput
and complete data redundancy. Utilizing an even number of physical disks (four or more) creates a RAID level 10 disk
group and/or virtual disk. Because RAID levels 1 and 10 use disk mirroring, half of the capacity of the physical disks is
utilized for mirroring. This leaves the remaining half of the physical disk capacity for actual storage. RAID 10 is
automatically used when a RAID level of 1 is chosen with four or more physical disks. RAID 10 works well for medium-
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