HP Netserver LXr Pro NetRAID Installation Guide

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4. If you:
•
want to define another array, click Back and repeat the steps listed above starting with step 3 in
Define an Array.
•
have identified all your arrays, click Next, Finish, and then OK.
NetRAID Assistant saves the array configuration and prompts that the array configuration has
changed. Click OK.
Initialize the Array
After you have defined the cluster’s arrays, you need to initialize the arrays you defined. HP NetRAID Assistant
initializes all arrays you have defined at the same time. To initialize all the arrays:
1. At the Would you like to Initialize? prompt, click OK.
HP NetRAID Initialization may be time consuming. Plan on 5 to 15 minutes per array.
2. When NetRAID initialization is complete, exit NetRAID Assistant.
3. Continue configuration using Windows NT Disk Administrator.
NOTE After you have finished defining and configuring the cluster’s arrays using HP NetRAID
Assistant, you will need to return to Defining RAID Arrays in Part 6 and finish
configuring the array using the Windows NT Disk Administrator utility.
Setting Up RAID 5 Arrays on an HP NetServer Cluster
The HP NetRAID adapter and proprietary HP NetRAID software can be used to organize the cluster’s disk
storage into RAID level 5 disk arrays. Each level 5 RAID array is composed of three hard (hot swap) drives
located in external shared storage cabinets.
RAID level 5 (striping with distributed parity) provides storage redundancy with good overall performance and
a minimum loss in storage capacity. With RAID 5 the equivalent of only one hard drive in the array is used for
redundancy. Note that each array supporting RAID 5 logical disks requires at least three physical drives.
Raid Level 5 Parity Distribution
Stripe Disk 1 Disk 2 Disk 3
1 Block 1.1 Block 1.2 Parity 1
2 Block 2.1 Parity 2 Block 2.2
3 Parity 3 Block 3.1 Block 3.2
The preceding table shows how data is distributed for RAID 5. As you can see, each stripe has one block
assigned to track parity data. Parity data can be used to reconstruct the data on that stripe if one of the disks
should fail. RAID 5 distributes parity information equally among all disk drives to equalize data I/O and
achieve better overall performance.