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7 Configuring RAID in a Dell workstation | 1.0
2 RAID Introduction
There are four RAID types supported in Precision 5820, 7820, 7920 Tower workstations: RAID0, RAID1,
RAID5, and RAID10. Other RAID types are available on the MegaRAID SAS controllers, but they have not
been validated on these platforms.
Note: Broadcom RAID controllers support JBOD (Just a Bunch of Disks) mode as well. Though JBOD mode
should work fine on Precision 5820, 7820, 7920 Tower workstations, JBOD mode is not officially supported
on these platforms. Single drive RAID0 is recommended for customers who need JBOD mode. Single drive
RAID0 provides almost same performance as JBOD, it also provides cache benefits while using 9460-16i
controller.
2.1 RAID 0 – Data striping across drives for faster read/write
performance
 Two or more drives of same size are required for RAID0.
 Single drive RAID0 volumes are also allowed on the MegaRAID SAS controllers. Single Drive RAID0 is
almost equivalent to using raw drives in JBOD mode, in addition it provides cache benefits while using the
9460-16i controller which has 4GB of cache memory.
 On multiple drive RAID0 volumes, Read/write operations are shared concurrently across multiple platters
and heads and so it provides better performance.
 Total volume capacity as seen by the Operating system is equal to the sum of the individual drive
capacities. e.g. if you use 4 drives of 1TB size, you get 4 x 1.0TB = 4.0TB
 Advantages – Higher space utilization compared to other volumes. Performance multiples as the number
of drives increase.
 Disadvantage – If any drive in the array fails, all data is lost. No redundancy.