Appendix B Designing RAID groups
The ATTO FastStream VT 5300 provides instant hardware data protection and intelligence to existing SCSI storage independent of the storage type.
CAUTION
Selecting RAID configuration causes all previous storage data on the drive to be erased. Make sure all of your information is backed up before setting up RAID groups.
The ATTO FastStream VT 5300 allows RAID functionality. In general, the process begins with individual drives also called block devices.
Note
If a drive has corrupt or outdated configuration data, that drive cannot be assigned to any RAID Group. Ensure all drives to be assigned to RAID groups are configured properly. Refer to Initialize and verify drives on page 17.
A RAID Group is a virtual, independent single drive whose data is written to physical drives according to a RAID algorithm. The ATTO FastStream VT 5300 supports JBOD, RAID Level 0, RAID Level 1, RAID Level 10 and RAID Level 5.
JBOD (Just a Bunch of Disks)
JBOD (Just a Bunch of Disks) configuration allows many individual drives to be available for normal storage operations with no special data protection.
Using the ATTO FastStream VT 5300 allows you to concatenate several individual drives into one large drive.
A JBOD drive can be constructed as a special case of a RAID Group. When multiple physical drives are assigned to a JBOD RAID Group, their storage areas appear as a single spanned area of storage. The ATTO FastStream VT 5300 supports 1 to 32 drives per
Exhibit
JBOD
Disk 0 | Disk 1 | Disk 2 |
D0 | D4 | D8 |
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D1 | D5 | D9 |
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D2 | D6 | D10 |
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D3 | D7 | D11 |
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RAID Level 0
RAID Level 0 (striping) is based on the fact that increased performance can be achieved by simultaneously accessing data across multiple drives, increasing data transfer rates while reducing average access time by overlapping drive seeks. RAID Level 0 groups provide data that is striped across several drives. Drives are accessed alternately, as if stacked one on top of the other.
RAID Level 0 provides no data protection. If one drive fails, all data within that stripe set is lost.
The ATTO FastStream VT 5300 supports 2 to 32 drives per RAID Level 0 group.
RAID Level 0 is used by applications requiring high performance for
Exhibit
RAID Level 0
Stripe | Disk 0 | Disk 1 | Disk 2 | Disk 3 | Disk 4 | Disk 5 |
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0 | D0 | D1 | D2 | D3 | D4 | D5 |
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1 | D6 | D7 | D8 | D9 | D10 | D11 |
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2 | D12 | D13 | D14 | D15 | D16 | D17 |
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3 | D18 | D19 | D20 | D21 | D22 | D23 |
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RAID Level 1
RAID Level 1 ensures the security of data by writing the exact same data simultaneously to two or more different drives. This application is for
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ATTO Technology Inc. FastStream VT 5300 Installation and Operation Manual
