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1.1 System Requirements
Operating System Support
NVRAID supports the following operating systems:
• Windows ® XP Home Edition
• Windows XP Professional Edition
• Windows 2000 Professional
• Windows 2003 Server
1.2 RAID Arrays
This section describes the following types of RAID arrays that
NVRAID supports: w RAID 0 : RAID 0 defines a disk striping scheme that improves the disk read and write times for many applications.
w RAID 1 : RAID 1 defines techniques for mirroring data.
w RAID 0+1 : RAID 0+1 combines the techniques used in RAID 0 and RAID 1 arrays.(Note: Only support P Serial Case).
w RAID 5 1 : RAID 5 provides fault tolerance and better utilization of
disk capacity.(Note: Only support P Serial Case).
w Spanning (JBOD) : JBOD provides a method for combining drives of different sizes into one large disk.
RAID 0
L How RAID 0 Works
RAID 0 involves no parity calulations to complicate the write operation. This makes RAID 0 ideal for applications that require high bandwidth but do not require fault tolerance. RAID 0 has the best performance and capacity of any RAID level, but the lowest availability (no fault tolerance). If one drive fails, the entire array fails because part of the data is missing with no way to recover it other than restoring from a backup.
Figure 1.1 RAID 0 Array Diagram
Block1
Block3
Block5
Block2
Block4
Block6
Summary of Features and Benefits
Benefits
Drawbacks
Uses
Drives
Provides increased data throughput, especially for large files. No capacity loss penalty for parity.
Does not deliver any fault tolerance.
If any drive in the array fails, all data is lost.
Intended for non-critical data requiring high data throughput, or any environment that does not require fault tolerance.
Minimum: 1. Maximum: Up to 6 or 8, depending on the platform.
Fault Tolerance No.
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RAID 1
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How RAID 1 Works
In a RAID 1 array, every read and write is actually carried out in parallel across two disk drives. The mirrored— or backup— copy of the data can reside on the same disk or on a second redundant drive in the array. RAID 1 provides a hot-standby copy of data if the active volume or drive is corrupted or becomes unavailable because of a hardware failure. RAID 1 techniques can be applied for highavailability solutions, or as a form of automatic backup that eliminates tedious manual backups to more expensive and less reliable media.
RAID 1 provides complete data redundancy, but at the cost of doubling the required data storage capacity, resulting in
50% capacity utilization. Performance is roughly the same as for a single drive, although in some instances the dual wr it e ma y b e s om ew h a t slower.
Block1
Block2
Block3
Block1
Block2
Block3
Figure 1.2 RAID 1 Array Diagram
Summary of Features and Benefits
Benefits
Drawbacks
Uses
Provides 100% data redundancy. Should one drive fail, the controller switches to the other drive.
Requires two drives for the storage space of one drive. Performance is impaired during drive rebuilds.
RAID 1 is ideal for small databases or any other application that requires fault tolerance and minimal capacity.
Drives Minimum, 2. Maximum, 2.
Fault Tolerance Yes.
RAID 0+1
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How RAID 0+1 Works
RAID 0 drives can be mirrored using RAID 1 techniques, resulting in a RAID 0+1 solution for improved performance plus resiliency.
Block1
Block3
Block5
Block2
Block4
Block6
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Block1
Block3
Block5
Figure 1.3 RAID 0+1 Array Diagram
Block2
Block4
Block6
The controller combines the performance of data striping (RAID 0) and the fault tolerance of disk mirroring (RAID 1). Data is striped across multiple drives and duplicated on another set of drives.
Summary of Features and Benefits
Benefits
Optimizes for both fault tolerance and performance, allowing for automatic redundancy.
May be simultaneously used with other RAID levels in an array, and allows for spare disks.
Drawbacks
Drives
Requires twice the available disk space for data redundancy, the same as RAID level 1.
Minimum: 4. Maximum: 6 or 8, depending on the platform.
Fault Tolerance Yes.
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