NEC Express5800/320Fd-LR User Manual page 94

4-34 Linux Setup
Creating Striping Array
Striping array (RAID 0) is a RAID device that distributes I/O requests issued to striping array to
each member. This function improves the I/O capacity and data writing/reading speed on striping
array. Available disk capacity on striping array is the total of all members, which is different from
redundant configuration RAID device (RAID 1 device). You must prepare individual hard disk
drives for the members of striping array to improve I/O capacity.
When you configure striping array only, the whole array will be unavailable and the fault tolerance
becomes low if a failure occurs on any of the members. However, you can configure the devices
that have both fault tolerance and I/O capacity (called "RAID1+0 device" in this document and
ftdiskadm) by configuring the member of the array with RAID 1 devices.
IMPORTANT:
You must add 4 hard disk drives to utilize the feature of striping array when you create the
array using ftdiskadm.
When you create striping array using ftdiskadm, you must take data backup because the data
written on the RAID 1 disappears as installing the existing RAID 1 device.
The size of the each RAID 1 devices installed in striping array is expected to be the same in
order to maximize the feature. (Prepare the same size partitions using the disk configuration
that is used when expanding hard disk drive).
You must execute the following operations as root user.
The following shows how to create striping array (RAID 1+0 device) using ftdiskadm. (The
following procedure is an example of installing the RAID 1 device "md4" configured on the hard
disk drives of slot 2 and 5, and the RAID 1 device "md6" configured on the hard disk drives of slot
3 and 6 in a striping array.)
Confirm the status of the RAID 1 device to be installed in striping array.
1.
# ftdiskadm
Command action
1 List RAID Arrays
2 List Internal Disks
3 Make Mirroring Arrays
4 Repair Mirroring Arrays (RAID1)
5 Delete Mirroring Arrays (RAID1)
6 Remove Disk Partitions (RAID1)
7 Make Striping Array
8 Delete Striping Array
c Configurations
q Quit
Command: 1
[List RAID Arrays]
Name Partition
==================================================================
< Mirroring Array (RAID1)
(RAID1)
(RAID1+0)
(RAID1+0)
(Label) Status
>
Member