Product Documentation

Managing the RAID disk allocation

Jun 13, 2017

NetScaler SDX 22040/22060/22080/22100/22120 appliances now include a Redundant Array of Independent Disks (RAID) controller, which can support up to eight physical disks. Multiple disks provide not only performance gains, but also enhanced reliability. Reliability is especially important for a NetScaler SDX appliance, because the appliance hosts a large number of virtual machines, and a disk failure affects mulitple virtual machines. The RAID controller on the Management Service supports the RAID 1 configuration, which implements disk mirroring. That is, two disks maintain the same data. If a disk in the RAID 1 array fails, its mirror immediately supplies all needed data.

Note: RAID functionality is supported only on NetScaler SDX 22040/22060/22080/22100/22120 Platform.

RAID 1 disk mirroring combines two physical drives in one logical drive. The usable capacity of a logical drive is equivalent to the capacity of one of its physical drives. Combining two 1-terabyte drives, for example, creates a single logical drive with a total usable capacity of 1-terabyte. This combination of drives appears to the appliance as a single logical drive.

The SDX appliance is shipped with a configuration that includes logical drive 0, which is allocated for the Management Service and XenServer, and logical drive 1, which is allocated for NetScaler instances that you will provision. To use additional physical drives, you have to create new logical drives.

Viewing Drive Properties and Operations

A NetScaler SDX appliance supports a maximum of eight physical-drive slots, that is, a pair of four slots on each side of the appliance. You can insert physical drives into the slots. Before you can use a physical drive, you must make it part of a logical drive needs.

In the Management Service, the Configuration > System > RAID screen includes tabs for logical drives, physical drives, and storage repositories.

Logical Drives

On the Configuration > System > RAID > Logical Drives tab, you can view the name, state, size, of each logical drive, and information about its component physical drives. The following table describes the states of the virtual drive.

State Description
Optimal The virtual drive operating condition is good. All configured drives are online.
Degraded The virtual drive operating condition is not optimal. One of the configured drives has failed or is offline.
Failed The virtual drive has failed.
Offline The virtual drive is not available to the RAID controller.

You can also view the details the physical drives associated with the logical drive by selecting the logical drive and clicking Show Physical Drive.

To create a new logical drive

  1. Navigate to Configuration > System > RAID, and select the Logical Drives tab.
  2. Click Add.
  3. In the Create Logical Disk dialog box, select two slots that contain operational physical drives, and then click Create.

Physical Drives

A NetScaler SDX appliance supports a maximum of eight physical slots, that is, a pair of four slots on each side of the appliance. On the Configuration > System > RAID > Physical Drives tab, you can view the following information:
  • Slot—Physical slot associated with the physical drive.
  • Size—Size of the physical drive.
  • Firmware State—State of the firmware. Possible Values:
    • Online, spun up—Physical drive is up and is being controlled by RAID.
    • Unconfigured (good)—Physical drive is in good condition and can be added as a part of the logical drive pair.
    • Unconfigured (bad)—Physical drive is not in good condition and cannot be added as part of a logical drive.
  • Foreign State— Indicates if the disk is empty.
  • Logical Drive— Associated logical drive.

In the Physical Drives pane, you can perform the following actions on the physical drives:

  • Initialize—Initialize the disk. You can initialize the physical drive if it is not in good state and needs to be added as a part of logical drive pair.
  • Rebuild—Initiate a rebuild of the drive. When a drive in a drive group fails, you can rebuild the drive by re-creating the data that was stored on the drive before it failed. The RAID controller re-creates the data stored on the other drives in the drive group.
  • Locate—Locate the drive on the appliance, indicated by causing the Drive Activity LED associated with the drive to blinnk.
  • Stop Locate—Stop locating the drive on the appliance.
  • Prepare to Remove—Deactivate the selected physical drive so that it can be removed.

Storage Repository

On the Configuration > System > RAID > Storage Repository tab, you can view the status of storage repositories on NetScaler SDX appliance. You can also view information about a storage-repository drive that is not attached, and you can remove such a drive by selecting the it and then clicking Remove. The Storage Repository tab displays the following information about each storage repository:

  • Name—Name of the storage repository drive.
  • Is Drive Attached—Whether the storage repository is attached or not. If the drive is not attached, you can click Remove to delete.
  • Size—Size of the storage repository.
  • Utilized—Amount of storage-repository space in use.