Creating Software RAIDs

A software RAID consists of two or more physical hard disks combined to act as a single logical unit. Software RAIDs are created using special software and are meant for improving the disk performance and providing fault tolerance from disk errors.

You can create software RAIDs when installing Parallels Server Bare Metal on your server. To do this, select the Create custom layout radio button in the Partitioning window, and click Next . The main partitioning window appears:

The process of creating software RAIDs is similar to that used to create software RAIDs in most modern Linux distributions (e.g., Red Hat Enterprise Linux or CentOS) and includes the following stages:

1. Making software RAID partitions.
2. Creating RAID arrays (or devices) from the newly made software RAID partitions.

This section describes how to create a software RAID for the /vz partition when running the Parallels Server Bare Metal installer in the graphical mode. However, you can easily adapt the procedures shown here to create software RAIDs for other partitions (e.g., for the root partition) in both the graphical and text modes.

Making software RAID partitions

In the first step, you need to create two or more identical software RAID partitions for the /vz partition. These RAID partitions will then be used as the basis for making a RAID array.

To create a software RAID partition:

1. Click the RAID button in the main partitioning window to open the RAID Options dialog.

   

2. Make sure the Create a software RAID partition radio button is selected, and click OK . The Add Partition dialog appears.

   

3. In the Allowable Drives section, select the check box of the drive you want to use for the RAID. Make sure the check boxes of all the other drives are cleared. This is necessary because a software RAID partition can be situated on one disk drive only.
4. In the Size field, specify the size for the /vz partition. The /vz partition is intended to store all virtual machines and Containers data and should occupy as much disk space as possible.
5. Select Force to be a primary partition if you want to make the /vz partition a primary partition.
6. Click OK . The newly created software RAID partition will appear in the main partitioning window.

Repeat the steps above to create other software RAID partitions for the /vz partition. Their number will differ depending on the RAID configuration you want to implement. For example, if you are going to deploy the RAID 1 configuration where 2 mirrored hard drives are used, you need to create one more software RAID. Once you create it, your window should look like the following:

Creating RAID devices

Now that you have created the necessary RAID partitions for the /vz partition, you can make a RAID array on their basis. To do this:

1. Click the RAID button in the main partitioning window.

   

2. In the RAID Options dialog, select the Create a RAID device radio button, and click OK .

   

3. In the Make RAID Device dialog, set the parameters for the RAID device:
   • Specify a mount point in the Mount Point field. In our case, the mount point should be /vz .
   • Choose the filesystem type for the array in the File System Type field. ext3 is the recommended filesystem type to use on servers running Parallels Server Bare Metal.
   • Select a name for the RAID array in the RAID Device field. You can leave the name offered by default or specify your own one.
   • Choose the RAID level in the RAID Level field. For the /vz partition, you can choose any of the RAID levels available in the drop-down menu.
   • The RAID Members section lists all your software RAID partitions. Select the check boxes next to the RAID partitions you created for the /vz partition.
   • Specify the number of spare partitions in the Number of spares field. Spare partitions can be configured in RAID 1 and RAID 5 implementations only.

   When you are done, click OK . The created RAID array will appear in the Devices column under RAID Devices .

   

For more information on RAIDs, see https://raid.wiki.kernel.org/index.php/Linux_Raid .