Configuring MegaRAID for RAID Level 0
This guide will help you to configure your server’s disks with RAID 0, which will allow you to use all your disks usable space.
Last updated 2nd August 2018
Objective
Redundant Array of Independent Disks (RAID) is a utility that mitigates data loss on a server by replicating data across two or more disks.
The default RAID level for OVHcloud server installations is RAID 1, which doubles the space taken up by your data, effectively halving the usable disk space.
This guide will help you to configure your server’s disks with RAID 0, which will allow you to use all your disks' usable space.
Please note: RAID 0 provides NO FAULT TOLERANCE and NO DATA REDUNDANCY, making data loss in the event of disk failure highly likely.
Requirements
- a dedicated server with hardware RAID
- administrative (root) access to the server via SSH
Instructions
Using the OVHcloud Control Panel
In the OVHcloud Control Panel, click on the Bare Metal Cloud menu and then select your server by going to Dedicated Servers in the left-hand sidebar.
In the General Information tab, look for « System (OS) » and click on ... then on Install button to install a new operating system with your custom RAID 0 configuration.
Now select Install from an OVHcloud template and then click Next.
Select the operating system you want to install and then click Next.
Tick the boxes for Customise the hardware RAID configuration and Customise the partition configuration, then click Next.
Select raid0 from the RAID drop-down list and click Next.
Configure the partitions as you see fit and then click Next.
Finally, click Confirm.
After your server has been installed, check the partition sizes by logging on to the server via SSH and running the following command:
df -h
Using rescue mode
In the OVHcloud Control Panel, click on the Bare Metal Cloud menu and then select your server by going to Dedicated Servers in the left-hand sidebar.
In the General Information tab, look for « Boot » and click on ... then on Edit button to change the boot system.
Next, select Boot in rescue mode then select rescue64-pro from the drop-down list.
In the field "Send new login details to the following email address:", specify an alternative email address if you do not want the login credentials sent to your customer account’s primary address.
Click Next and then click Confirm on the following screen.
Once the change is completed, click on ... next to “Status” in the box labelled Service status. Select Restart and the server will restart into rescue mode.
When your server reboots, log in to it via SSH using the rescue mode credentials that were emailed to you.
From the command line, type the following commands to delete the existing RAID settings. All data in the RAID will be deleted:
MegaCli -CfgLdDel -L0 -a0
MegaCli -CfgLdDel -Lall -aAll
Type the following command to retrieve the slot device IDs of your disks:
MegaCli -PdList -aALL | egrep "Slot|Device ID"
Type the following commands to configure RAID level 0:
MegaCli -CfgLDAdd -R0[252:0,252:1] -a0
In this example, 252 is the ID of the drive enclosure.
After setting the new RAID level you can check the settings with the following command:
MegaCli -LDInfo -Lall -a0 |grep -i size
Go further
Join our community of users on https://community.ovh.com/en/
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