Hands-onRAID on Moxa Computer Prepared by: (40min)Date: mm-dd-yyyy

Definition of RAID

Redundant Array of Independent Disks Combine multiple physical disks into one

logical unit so to increase read/write performance or data redundancy.

Is NOT a reliable backup plan

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RAID levels

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LevelDescriptio

nMin # of drives**

Space Efficiency

Fault Tolerance

Read Benefit

Write Benefit

Image

RAID 0

Block-level striping without parity or mirroring.

2 1 none nX nX

RAID 1Mirroring without parity or striping.

2 1/n n−1 drives nX 1X

*Extract from http://en.wikipedia.org/wiki/RAID

Hardware RAID

RAID controller card- usually a PCIe expansion card- calculations are done by the controller (no CPU resource is needed)- high price- thermal/power issue

Intel I/O Controller Hub(ICH) - come with the computer but not all ICH supports RAID

- V2616 uses ICH9M-SFF, which supports RAID 0,1

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Software RAID

Done by OS, no extra hardware is required Uses CPU resource—performance depends

greatly on CPU speed Free tool on Linux: mdadm

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Using mdadmto configure RAID 0 on V2400 series

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Install mdadm

the root file system is set to be read-only, change to read-write:

#mount –o remount,rw / use apt-get install command to install mdadm

#apt-get install mdadm

* what is apt? Appendix A

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Package configuration window will appear, select Ok and click Enter

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Use the default setting. Select Ok and click Enter

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Insert USB disks

USB devices will be mounted automatically. You may use the following command can to check the filesystem:

#df –h

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the usb devices are mounted here

Create RAID device

unmount the USB devices first

#umount /dev/sdb1

#umount /dev/sdc1 create RAID device

#mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sdb /dev/sdc

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Create RAID device

Check the RAID device:

#mdadm --detail /dev/md0

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RAID level is 0

Create RAID device

Formate the disk

#mkfs -t ext3 /dev/md0

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Create RAID device

mount the device somewhere you want

#mkdir /home/raid_disk

#mount /dev/md0 /home/raid_disk use df command to check the filesysytem

again

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the usb devices became /dev/md0, with the disk size of 15G and is mounted to assigned path

Auto-mount the RAID device

edit /etc/rc.local like below, the script here will be executed after boot.

try reboot the computer with modified and unmodified rc.local and see if /dev/md0 is mounted correctly.

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add this line

Appendix A: what is apt?

Advanced Packaging tool used on Debian linux distribution to handle installation and removal of software packages.

Important files and commands:

/etc/apt/sources.list : Locations to fetch packages from. If your cannot fetch the package, you may want to check if the sources list is still valid.

apt-get install package_name : install package_name

apt-cache search text : Find package relate to text

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Configure RAID 0 on V2616

Using Intel Rapid Storage Technology

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V2616 RAID Function Configuration

The V2616 computers have two storage trays that allow users to install two 2.5-inch SATA hard disks, and support RAID 0 and RAID 1 functions for data backup and recovery.

Before using the RAID functions, you need to install two SATA hard disks with the same capacity in the V2616 computer.

1. Check disk management, right-click on the two disks to initialize.

Configuring RAID 0 Function

2. Launch the Intel Rapid Storage Technology program

3. Press Create button, select Optimized disk performance (RAID 0) option, and then click Next.

4. Use the following settings to save the data to another disk.a. Select the disks installed on the computer.b. Specify the volume size by adjusting the scroll bar.c. Determine the data strip size.d. Check Enable volume write-back cache.

a

bc

d

5. Confirm the settings and then click Create Volume.

6. Click OK when volume creation is complete.

7. Check the storage status.

8. Check Disk Management. Right-click on the disk to initialize disk, and then click OK.

9. Right-click on the disk to use New Simple Volume Wizard. Click Next to continue.

10. Enter the partition size in the blank, and then click Next to continue.

11. Select Assign the following drive letter, and then click Next to continue.

12. Select Format this partition with the following settings.a. File system: NTFT.b. Allocation unit size: Default.c. Volume label: New Volume (the default value).d. Check Perform a quick format.

ab

cd

13. Click Finish to close the New Partition Wizard.

14. When finished, you may check the disk status from Disk Management column.

15. Check the My Computer.