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documentation.suse.com / SUSE Linux Enterprise Server Documentation / Storage Administration Guide / Software RAID / Configuring Software RAID for the Root Partition
Applies to SUSE Linux Enterprise Server 15 SP2

8 Configuring Software RAID for the Root Partition

In SUSE Linux Enterprise Server, the Device Mapper RAID tool has been integrated into the YaST Partitioner. You can use the partitioner at install time to create a software RAID for the system device that contains your root (/) partition. The /boot partition cannot be stored on a RAID partition unless it is RAID 1.

8.1 Prerequisites for Using a Software RAID Device for the Root Partition

Ensure that your configuration meets the following requirements:

  • You need two hard disks to create the RAID 1 mirror device. The hard disks should be similarly sized. The RAID assumes the size of the smaller drive. The block storage devices can be any combination of local (in or directly attached to the machine), Fibre Channel storage subsystems, or iSCSI storage subsystems.

  • A separate partition for /boot is not required if you install the boot loader in the MBR. If installing the boot loader in the MBR is not an option, /boot needs to reside on a separate partition.

  • For UEFI machines, you need to set up a dedicated /boot/efi partition. It needs to be VFAT-formatted, and may reside on the RAID 1 device to prevent booting problems in case the physical disk with /boot/efi fails.

  • If you are using hardware RAID devices, do not attempt to run software RAIDs on top of it.

  • If you are using iSCSI target devices, you need to enable the iSCSI initiator support before you create the RAID device.

  • If your storage subsystem provides multiple I/O paths between the server and its directly attached local devices, Fibre Channel devices, or iSCSI devices that you want to use in the software RAID, you need to enable the multipath support before you create the RAID device.

8.2 Setting Up the System with a Software RAID Device for the Root (/) Partition

  1. Start the installation with YaST and proceed as described in Chapter 8, Installation Steps until you reach the Suggested Partitioning step.

  2. Click Expert Partitioner to open the custom partitioning tool. YaST makes a default proposal, you can use this proposal by clicking Start with Current Proposal. You can also discard the suggested proposal by clicking Start with Existing Partitions.

  3. (Optional) If there are iSCSI target devices that you want to use, you need to enable the iSCSI Initiator software by choosing Configure › Configure iSCSI from the lower right section of the screen. Refer to Chapter 15, Mass Storage over IP Networks: iSCSI for further details.

  4. (Optional) You may need to configure multiple network interfaces for FCoE, click Configure FCoE to do so.

  5. (Optional) In case you have used the suggested proposal and you do not need it anymore. Click Rescan Devices to delete the proposed partitioning.

  6. Set up the Linux RAID format for each of the devices you want to use for the software RAID. You should use RAID for /, /boot/efi, or swap partitions.

    1. In the left panel, select Hard Disks and select the device you want to use. Click the Partitions tab and then click Add Partition.

    2. Under New Partition Size, specify the size to use, then click Next.

    3. Under Role, choose Raw Volume (unformatted).

    4. Select Do not format and Do not mount. Set the Partition ID to Linux RAID.

    5. Click Next and repeat these instructions for the second partition.

  7. Create the RAID device for the / partition.

    1. In the left panel, select RAID and then Add RAID.

    2. Set the desired RAID Type for the / partition and the RAID name to system.

    3. Select the two RAID devices you prepared in the previous step from the Available Devices section and Add them.

      RAID devices selection

      Proceed with Next.

    4. Under RAID Options, select the chunk size from the drop-down box. Sticking with the default is a safe choice.

    5. In the left panel, click RAID and then select the system. Click Edit.

    6. Under Role, select Operating System and proceed with Next.

    7. Select the File System and set the mount point to /. Leave the dialog with Next.

  8. The software RAID device is managed by Device Mapper, and creates a device under the /dev/md/system path.

  9. Optionally for UEFI machines, use similar steps to create the /boot/efi mounted partition. Remember that only RAID 1 is supported for /boot/efi, and the partition needs to be formatted with the FAT file system.

    RAID devices selection with UEFI
    Figure 8.1: /, /boot/efi, and swap on RAIDs
  10. Click Accept to leave the partitioner.

    The new proposal appears on the Suggested Partitioning page.

  11. Continue with the installation. For UEFI machines with a separate /boot/efi partition, click Booting on the Installation Settings screen and set GRUB2 for EFI as the Boot Loader. Check that the Enable Secure Boot Support option is activated.

    Whenever you reboot your server, Device Mapper is started at boot time so that the software RAID is automatically recognized, and the operating system on the root (/) partition can be started.