Getting Started Guide for Cisco UCS E-Series Servers, Release 2.x
Managing RAID
Downloads: This chapterpdf (PDF - 1.64MB) The complete bookPDF (PDF - 5.75MB) | The complete bookePub (ePub - 2.02MB) | Feedback

Managing RAID


Note


If you purchased E-Series Server Option 1 (E-Series Server without preinstalled operating system or hypervisor), and you want to store data files on local Redundant Array of Inexpensive Disks (RAID), you must configure RAID.


This chapter includes the following sections:

RAID Options

You can choose to store the E-Series Server data files on local Redundant Array of Inexpensive Disks (RAID). The following RAID levels are supported:

  • The single-wide E-Series Server supports RAID 0 and RAID 1 levels.
  • The double-wide E-Series Server supports RAID 0, RAID 1, and RAID 5 levels.
  • The double-wide E-Series Server with the PCIe option supports RAID 0 and RAID 1 levels.

RAID 0

With RAID 0, the data is stored evenly in stripe blocks across one or more disk drives without redundancy (mirroring). The data in all of the disk drives is different.

Figure 1. RAID 0

Compared to RAID 1, RAID 0 provides additional storage because both disk drives are used to store data. The performance is improved because the read and write operation occurs in parallel within the two disk drives.

However, there is no fault tolerance, error checking, hot spare, or hot-swapping. If one disk drive fails, the data in the entire array is destroyed. Because there is no error checking or hot-swapping, the array is susceptible to unrecoverable errors.

RAID 1

RAID 1 creates a mirrored set of disk drives, where the data in both the disk drives is identical, providing redundancy and high availability. If one disk drive fails, the other disk drive takes over, preserving the data.

RAID 1 also allows you to use a hot spare disk drive. The hot spare drive is always active and is held in readiness as a hot standby drive during a failover.

Figure 2. RAID 1

RAID 1 supports fault tolerance and hot-swapping. When one disk drive fails, you can remove the faulty disk drive and replace it with a new disk drive.

However, compared to RAID 0, there is less storage space because only half of the total potential disk space is available for storage and there is an impact on performance.

RAID 5

With RAID 5, the data is stored in stripe blocks with parity data staggered across all disk drives, providing redundancy at a low cost.

Figure 3. RAID 5

RAID 5 provides more data storage capacity than RAID 1 and better data protection than RAID 0. It also supports hot swapping; however, RAID 1 offers better performance.

Non-RAID

When the disk drives of a computer are not configured as RAID, the computer is in non-RAID mode. Non-RAID mode is also referred to as Just a Bunch of Disks or Just a Bunch of Drives (JBOD). Non-RAID mode does not support fault tolerance, error checking, hot-swapping, hot spare, or redundancy.

Summary of RAID Options

RAID Option Description Advantages Disadvantages

RAID 0

Data stored evenly in stripe blocks without redundancy

  • Better storage
  • Improved performance
  • No error checking
  • No fault tolerance
  • No hot-swapping
  • No redundancy
  • No hot spare

RAID 1

Mirrored set of disk drives and an optional hot spare disk drive

  • High availability
  • Fault tolerance
  • Hot spare
  • Hot-swapping
  • Less storage
  • Performance impact

RAID 5

Data stored in stripe blocks with parity data staggered across all disk drives

  • Better storage efficiency than RAID 1
  • Better fault tolerance than RAID 0
  • Low cost of redundancy
  • Hot-swapping
  • Slow performance

Non-RAID

Disk drives not configured for RAID

Also referred to as JBOD

  • Portable
  • No error checking
  • No fault tolerance
  • No hot-swapping
  • No redundancy
  • No hot spare

Configuring RAID

You can use the CIMC GUI or the WebBIOS, which is accessible from the KVM console, to configure RAID.

Configuring RAID Using the CIMC GUI

Use this procedure to configure the RAID level, strip size, host access privileges, drive caching, and initialization parameters on a virtual drive. You can also use this procedure to designate the drive as a hot spare drive and to make the drive bootable.

Procedure
    Step 1   In the Navigation pane, click the Server tab.
    Step 2   On the Server tab, click RAID. Do one of the following:
    • If the Configure Virtual Drive dialog box does not appear, proceed to the next step.

    • If the Configure Virtual Drive dialog box appears, and the virtual drives are not configured, complete the fields as shown in Step 5.

    Step 3   In the tabbed menu of the Storage Cards area, click the Virtual Drive Info tab.
    Figure 4. Virtual Drive Info Tab



    Step 4   In the Actions area of the Virtual Drive Info tab, click Create.

    The Configure Virtual Drive dialog box appears.

    Figure 5. Configure Virtual Drive Dialog Box



    Step 5   Complete the following fields as appropriate:
    Name Description

    Available Drives table

    Displays the drives that are available for RAID configuration.

    Note   

    To move a drive, click and drag a drive to the appropriate table.

    Selected Drives table

    Displays the drives that are selected for RAID configuration.

    Note   

    To move a drive, click and drag a drive to the appropriate table.

    RAID Level drop-down list

    The RAID level options. This can be one of the following:

    • RAID 0—Block striping.
    • RAID 1—Mirroring.
    • RAID 5—Block striping with parity.
    Note   

    The single-wide E-Series Server supports RAID 0 and RAID 1 levels. The double-wide E-Series Server supports RAID 0, RAID 1, and RAID 5 levels. The double-wide E-Series Server with the PCIe option supports RAID 0 and RAID 1 levels.

    Name field

    The name of the virtual drive.

    Enter a maximum of 15 characters. The characters can have numbers and upper- or lower-case letters. Special characters are not supported.

    Strip Size drop-down list

    The strip size options. This can be one of the following:

    • 64 KB
    • 32 KB
    • 16 KB
    • 8 KB

    Initialization drop-down list

    How the controller initializes the drives. This can be one of the following:

    • Quick—The controller initializes the drive quickly. This is the default and recommended option.
    • Full—The controller does a complete initialization of the new configuration.
      Note   

      Depending on the size of the drives, full initialization can take several hours to complete. To view the progress, see the Initialize Progress and Initialize Time Elapsed fields in the General area.

    • None—The controller does not initialize the drives.

    Drive Cache drop-down list

    How the controller handles drive caching. This can be one of the following:

    • Disable—Caching is disabled on the drives.
      Note   

      This is the default and recommended option.

    • Unchanged—The controller uses the caching policy specified on the drive. This is the default and recommended option.
    • Enable—Caching is enabled on the drives. This option minimizes the delay in accessing data.
      Caution   

      Enabling Drive Cache, voids all warranty on the hard disk drives. This configuration option is not supported. Use this option at your own risk.

    Access Policy drop-down list

    Configures host access privileges. This can be one of the following:

    • Read-Write—The host has full access to the drive.
    • Read Only—The host can read only data from the drive.
    • Blocked—The host cannot access the drive.

    Set this Virtual Drive Bootable check box

    How the controller boots the drive. This can be one of the following:

    • Enable—The controller makes this drive bootable.
    • Disable—This drive is not bootable.
    Note   

    If you plan to install an operating system or Hypervisor into the RAID array, we recommend that you check this check box.

    Use the Remaining Drive as Hot Spare check box

    Designates the drive that is in the Available Drives table as a hot spare drive.

    Note   

    Applicable for RAID 1 only. This check box is greyed out for other RAID levels.

    Applicable for double-wide E-Series Servers.

    Step 6   Review the RAID configuration, and then click Confirm to accept the changes.

    Configuring RAID Using the WebBIOS

    Procedure
      Step 1   In the Navigation pane, click the Server tab.
      Step 2   On the Server tab, click Summary.
      Step 3   From the Actions area, click Launch KVM Console.

      The KVM Console opens in a separate window.

      Step 4   From the Server Summary page, click Power Cycle Server to reboot the server.
      Step 5   Press the Ctrl key, and then press H during bootup to access the WebBIOS.

      The Adapter Selection page from LSI Logic appears, which allows you to configure RAID. For information about this page, see the LSI Logic documentation.

      Figure 6. WebBIOS




      What to Do Next

      If you purchased E-Series Server Option 1 (E-Series Server without preinstalled operating system or hypervisor), install the operating system. See Installing the Operating System or Hypervisor.