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Disk sizes and capabilities

Using disks of various sizes  Top

Guideline for using fibre channel disks of various sizes

You can use fibre channel disks of various sizes with the same appliance, up to and including 18-GB, 36-GB, and 72-GB disks. However, unlike Network Appliance filers, the NetCache appliance does not support mixing fibre channel disks of different sizes in the same disk enclosure; they must be in separate enclosures.

The following table shows a sample configuration.

Enclosure

Data

Data

Parity

Hot Spare

Enclosure 1

Disk 0

(9-GB)

Disk 1

(9-GB)

Disk 2

(9-GB)

Disk 3

(9-GB)

Enclosure 2

Disk 0

(18-GB)

Disk 1

(18-GB)

Disk 2

(18-GB)

Disk 3

(18-GB)

Guideline for using SCSI disks of various sizes

You can use SCSI disks of various sizes with the same appliance, up to and including 18-GB, 36-GB, and 72-GB disks. Additionally, the appliance does not support mixing SCSI disks of different sizes in the same SCSI backplane.

The following table shows a sample configuration.

Backplane

Data

Data

Parity

Hot Spare

Backplane 1

Disk 0

(9-GB)

Disk 1

(36-GB)

Disk 2

(9-GB)

Disk 3

(18-GB)

Backplane 2

Disk 0

(9-GB)

Disk 1

(72-GB)

Disk 2

(18-GB)

Disk 3

(18-GB)

Available C1200 disk roles and capabilities  Top

The following scenarios describe various disk configurations that are available on the C1200 system.

Note
On the C1200 system, 36-GB and 72-GB size disks are available. The following table shows examples for 72-GB disks.

Disks/size

Configuration

Result

Single disk --
72-GB

RAID-0: 1 data = 72-GB raw capacity

Lowest cost, no redundancy. If a disk fails, you swap the disk (or in the case of the C1100 or C1105 models, the appliance itself).

Caution
If a disk fails, a full shutdown, power off, and reinstallation of software and licenses are required. All data is lost from the disks.

Multi-disk --
two disks, 72-GB

RAID-4: 1 data + 1 parity mirrored = 72-GB raw capacity

Redundancy. If a disk fails, the appliance will still run but it will run in degraded mode.

For details, see Running in degraded mode.

Multi-disk --
three disks, 72-GB

RAID-4: 1 data + 1 parity + 1 hot spare = 72-GB raw capacity

Highest reliability. If a disk fails, the appliance will still run, and the hot spare disk will be automatically promoted to the active file system, replacing the failed disk.

If another disk fails after that process is complete, the appliance will enter degraded mode and behave like a two-disk system.

Multi-disk --
three disks, 72-GB

RAID-4: 2 data disks + 1 parity = 144-GB raw capacity

Higher capacity with redundancy. If a disk fails, the appliance will enter degraded mode and behave like a two-disk system.

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