Raid Levels - Seagate NAS OS 4 U User Manual

Note: Step-by-step instructions on how to create a new volume are available in New network
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.volume wizard
RAID comparisons
The level of RAID available to a volume is contingent upon the amount of hard drives in the enclosure. For
example, a volume with four hard drives supports all levels of RAID except for RAID 1, which is not compatible
with volumes greater than three hard drives. The New network volume wizard offers star ratings for each RAID
at the RAID selection step. Choose a RAID's radio button to review its strengths and weaknesses in the center
.of the window
Example 1: When making comparisons in a volume with four hard drives, RAID 0 is the best choice for storage
capacity. However, it has a major weakness: no data protection. Further, RAID 0 performance approximates
.that of RAID 5, which provides data protection if a hard drive fails
Example 2: Both RAID 6 and SimplyRAID Dual offer data protection even if two hard drives fail. However,
.SimplyRAID will optimize storage capacity far better than RAID 6 in mixed capacity configurations

RAID levels

NAS OS SimplyRAID
Most RAID modes use equal disk capacities among the pool of hard drives to protect data. Rather then lose
storage capacity overhead in mixed hard drive environments, SimplyRAID preserves the extra space for use
when new hard drives are added to the enclosure. This means that, unlike standard RAID models, you can
easily expand the array without losing data. For example, two 1TB hard drives will create a RAID 1 array
without any storage capacity overhead. However, one 1TB hard drive paired with one 2TB hard drive only
creates 1TB of protection since data cannot surpass the storage capacity of the smallest hard drive.
.SimplyRAID will calculate the overhead and prepare it for future expansion
(JBOD (Just a Bunch of Disks
104 10/18/16 Seagate NAS OS 4