Because a new LUN has no partition or file system when the Linux host first discovers it, you must format the LUN before it can be used. Optionally, you can create a file system on the LUN.

Before you begin

Make sure you have the following:

  • A LUN that is discovered by the host.

  • A list of available disks. (To see available disks, run the ls command in the /dev/mapper folder.)

About this task

You can initialize the disk as a basic disk with a GUID partition table (GPT) or Master boot record (MBR).

Format the LUN with a file system such as ext4. Some applications do not require this step.

Steps
  1. Retrieve the SCSI ID of the mapped disk by issuing the multipath -ll command.

    The SCSI ID is a 33-character string of hexadecimal digits, beginning with the number 3. If user-friendly names are enabled, Device Mapper reports disks as mpath instead of by a SCSI ID.

    # multipath -ll
    mpathd(360080e5000321bb8000092b1535f887a) dm-2 Lenovo DE_Series
    size=1.0T features='3 queue_if_no_path pg_init_retries 50' hwhandler='1 alua' wp=rw
    |-+- policy='service-time 0' prio=50 status=active
    | |- 16:0:4:4 sde     69:144 active ready running
    | `- 15:0:5:4 sdf     65:176 active ready running
    `-+- policy='service-time 0' prio=10 status=enabled
      |- 16:0:5:4 sdg     70:80  active ready running
      `- 15:0:1:4 sdh     66:0   active ready running
  2. Create a new partition according to the method appropriate for your Linux OS release.

    Typically, characters identifying the partition of a disk are appended to the SCSI ID (the number 1 or p3 for instance).

    # parted -a optimal -s -- /dev/mapper/360080e5000321bb8000092b1535f887a mklabel
    gpt mkpart primary ext4 0% 100%
  3. Create a file system on the partition.

    The method for creating a file system varies depending on the file system chosen.

    # mkfs.ext4 /dev/mapper/360080e5000321bb8000092b1535f887a1
  4. Create a folder to mount the new partition.

    # mkdir /mnt/ext4
  5. Mount the partition.

    # mount /dev/mapper/360080e5000321bb8000092b1535f887a1 /mnt/ext4