Amazon EBS and RAID configuration

Create the Amazon EBS volumes for your array. For more information, see Create an Amazon EBS volume.

Attach the Amazon EBS volumes to the instance that you want to host the array. For more information, see Attach an Amazon EBS volume to an Amazon EC2 instance.

Use the mdadm command to create a logical RAID device from the newly attached Amazon EBS volumes. Substitute the number of volumes in your array for number_of_volumes and the device names for each volume in the array (such as /dev/xvdf) for device_name. You can also substitute MY_RAID with your own unique name for the array.

To create a RAID 0 array, run the following command (note the --level=0 option to stripe the array):

[ec2-user ~]$ sudo mdadm --create --verbose /dev/md0 --level=0 --name=MY_RAID --raid-devices=number_of_volumes device_name1 device_name2

Allow time for the RAID array to initialize and synchronize. You can track the progress of these operations with the following command:

[ec2-user ~]$ sudo cat /proc/mdstat

The following is example output:

Personalities : [raid0]
md0 : active raid0 xvdc[1] xvdb[0]
      41910272 blocks super 1.2 512k chunks

unused devices: <none>

In general, you can display detailed information about your RAID array with the following command:

[ec2-user ~]$ sudo mdadm --detail /dev/md0

The following is example output:

/dev/md0:
           Version : 1.2
     Creation Time : Wed May 19 11:12:56 2021
        Raid Level : raid0
        Array Size : 41910272 (39.97 GiB 42.92 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Wed May 19 11:12:56 2021
             State : clean
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

        Chunk Size : 512K

Consistency Policy : none

              Name : MY_RAID
              UUID : 646aa723:db31bbc7:13c43daf:d5c51e0c
            Events : 0

    Number   Major   Minor   RaidDevice State
       0     202       16        0      active sync   /dev/sdb
       1     202       32        1      active sync   /dev/sdc

Create a file system on your RAID array, and give that file system a label to use when you mount it later. For example, to create an ext4 file system with the label MY_RAID, run the following command:

[ec2-user ~]$ sudo mkfs.ext4 -L MY_RAID /dev/md0

Depending on the requirements of your application or the limitations of your operating system, you can use a different file system type, such as ext3 or XFS (consult your file system documentation for the corresponding file system creation command).

To ensure that the RAID array is reassembled automatically on boot, create a configuration file to contain the RAID information:

[ec2-user ~]$ sudo mdadm --detail --scan | sudo tee -a /etc/mdadm.conf

Create a new ramdisk image to properly preload the block device modules for your new RAID configuration:

[ec2-user ~]$ sudo dracut -H -f /boot/initramfs-$(uname -r).img $(uname -r)

Create a mount point for your RAID array.

[ec2-user ~]$ sudo mkdir -p /mnt/raid

Finally, mount the RAID device on the mount point that you created:

[ec2-user ~]$ sudo mount LABEL=MY_RAID /mnt/raid

Your RAID device is now ready for use.

(Optional) To mount this Amazon EBS volume on every system reboot, add an entry for the device to the /etc/fstab file.

1. Create a backup of your /etc/fstab file that you can use if you accidentally destroy or delete this file while you are editing it.

   [ec2-user ~]$ sudo cp /etc/fstab /etc/fstab.orig

2. Open the /etc/fstab file using your favorite text editor, such as nano or vim.

3. Comment out any lines starting with "UUID=" and, at the end of the file, add a new line for your RAID volume using the following format:

   device_label mount_point file_system_type fs_mntops fs_freq fs_passno

   The last three fields on this line are the file system mount options, the dump frequency of the file system, and the order of file system checks done at boot time. If you don't know what these values should be, then use the values in the example below for them (defaults,nofail 0 2). For more information about /etc/fstab entries, see the fstab manual page (by entering man fstab on the command line). For example, to mount the ext4 file system on the device with the label MY_RAID at the mount point /mnt/raid, add the following entry to /etc/fstab.

   Note

   If you ever intend to boot your instance without this volume attached (for example, so this volume could move back and forth between different instances), you should add the nofail mount option that allows the instance to boot even if there are errors in mounting the volume. Debian derivatives, such as Ubuntu, must also add the nobootwait mount option.

   LABEL=MY_RAID       /mnt/raid   ext4    defaults,nofail        0       2

4. After you've added the new entry to /etc/fstab, you need to check that your entry works. Run the sudo mount -a command to mount all file systems in /etc/fstab.

   [ec2-user ~]$ sudo mount -a

   If the previous command does not produce an error, then your /etc/fstab file is OK and your file system will mount automatically at the next boot. If the command does produce any errors, examine the errors and try to correct your /etc/fstab.

   Warning

   Errors in the /etc/fstab file can render a system unbootable. Do not shut down a system that has errors in the /etc/fstab file.

5. (Optional) If you are unsure how to correct /etc/fstab errors, you can always restore your backup /etc/fstab file with the following command.

   [ec2-user ~]$ sudo mv /etc/fstab.orig /etc/fstab

Create the Amazon EBS volumes for your array. For more information, see Create an Amazon EBS volume.

Attach the Amazon EBS volumes to the instance that you want to host the array. For more information, see Attach an Amazon EBS volume to an Amazon EC2 instance.

Connect to your Windows instance. For more information, see Connect to your Windows instance.

Open a command prompt and type the diskpart command.

diskpart

Microsoft DiskPart version 6.1.7601
Copyright (C) 1999-2008 Microsoft Corporation.
On computer: WIN-BM6QPPL51CO

At the DISKPART prompt, list the available disks with the following command.

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online           30 GB      0 B
  Disk 1    Online            8 GB      0 B
  Disk 2    Online            8 GB      0 B

Identify the disks you want to use in your array and take note of their disk numbers.

Each disk you want to use in your array must be an online dynamic disk that does not contain any existing volumes. Use the following steps to convert basic disks to dynamic disks and to delete any existing volumes.

1. Select a disk you want to use in your array with the following command, substituting n with your disk number.

   DISKPART> select disk n
   
   Disk n is now the selected disk.

2. If the selected disk is listed as Offline, bring it online by running the online disk command.

3. If the selected disk does not have an asterisk in the Dyn column in the previous list disk command output, you need to convert it to a dynamic disk.

   DISKPART> convert dynamic

   Note

   If you receive an error that the disk is write protected, you can clear the read-only flag with the ATTRIBUTE DISK CLEAR READONLY command and then try the dynamic disk conversion again.

4. Use the detail disk command to check for existing volumes on the selected disk.

   DISKPART> detail disk
   
   XENSRC PVDISK SCSI Disk Device
   Disk ID: 2D8BF659
   Type   : SCSI
   Status : Online
   Path   : 0
   Target : 1
   LUN ID : 0
   Location Path : PCIROOT(0)#PCI(0300)#SCSI(P00T01L00)
   Current Read-only State : No
   Read-only  : No
   Boot Disk  : No
   Pagefile Disk  : No
   Hibernation File Disk  : No
   Crashdump Disk  : No
   Clustered Disk  : No
   
     Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
     ----------  ---  -----------  -----  ----------  -------  ---------  --------
     Volume 2     D   NEW VOLUME   FAT32  Simple      8189 MB  Healthy

   Note any volume numbers on the disk. In this example, the volume number is 2. If there are no volumes, you can skip the next step.

5. (Only required if volumes were identified in the previous step) Select and delete any existing volumes on the disk that you identified in the previous step.

   Warning

   This destroys any existing data on the volume.

   1. Select the volume, substituting n with your volume number.

      DISKPART> select volume n
      Volume n is the selected volume.

   2. Delete the volume.

      DISKPART> delete volume
      
      DiskPart successfully deleted the volume.

   3. Repeat these substeps for each volume you need to delete on the selected disk.

6. Repeat Step 6 for each disk you want to use in your array.

Verify that the disks you want to use are now dynamic. In this case, we're using disks 1 and 2 for the RAID volume.

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online           30 GB      0 B
  Disk 1    Online            8 GB      0 B   *
  Disk 2    Online            8 GB      0 B   *

Create your raid array. On Windows, a RAID 0 volume is referred to as a striped volume.

To create a striped volume array on disks 1 and 2, use the following command (note the stripe option to stripe the array):

DISKPART> create volume stripe disk=1,2
DiskPart successfully created the volume.

Verify your new volume.

DISKPART> list volume

  DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     C                NTFS   Partition     29 GB  Healthy    System
  Volume 1                      RAW    Stripe        15 GB  Healthy

Note that the Type column now indicates that Volume 1 is a stripe volume.

Select and format your volume so that you can begin using it.

1. Select the volume you want to format, substituting n with your volume number.

   DISKPART> select volume n
   
   Volume n is the selected volume.

2. Format the volume.

   Note

   To perform a full format, omit the quick option.

   DISKPART> format quick recommended label="My new volume"
   
     100 percent completed
   
   DiskPart successfully formatted the volume.

3. Assign an available drive letter to your volume.

   DISKPART> assign letter f
   
   DiskPart successfully assigned the drive letter or mount point.

Your new volume is now ready to use.