Managing RAID disk allocation on the SDX 22000 platform

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 an SDX appliance, because the appliance hosts many virtual machines, and a disk failure affects multiple 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.

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 and logical drive 1. Logical drive 0 is allocated for the Management Service and the Citrix Hypervisor and logical drive 1 is allocated for the NetScaler instances that you provision. To use more physical drives, you have to create new logical drives.

View drive properties and operations

An 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.

In the Management Service, theConfiguration > System > RAIDscreen includes tabs for logical drives, physical drives, and storage repositories.

Logical drives

On theConfiguration > System > RAID > Logical Drives选项卡上,您可以查看名称、状态、大小,每个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 clickingShow Physical Drive.

To create a new logical drive

1. Navigate toConfiguration>System>RAID, and select theLogical Drivestab.
2. ClickAdd.
3. In theCreate Logical Disk对话框中,选择两个slots that contain operational physical drives, and then clickCreate.

Physical drives

An SDX appliance supports a maximum of eight physical slots, that is, a pair of four slots on each side of the appliance. On theConfiguration > System > RAID > Physical Drivestab, 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 thePhysical Drivespane, 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 must be added as a part of the 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 blink.
• 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 theConfiguration > System > RAID > Storage Repositorytab, you can view the status of storage repositories on the 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 it and then clickingRemove. TheStorage Repositorytab 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 clickRemoveto delete.
• Size:—Size of the storage repository.
• Utilized:—Amount of storage-repository space in use.

Add a logical drive to the SDX 22000 appliance

To add an extra logical drive to the SDX 22000 platform:

1. Log on to the Management Service.
2. Navigate toConfiguration > System > RAID.
3. On the back of the SDX 22000 appliance, insert the two blank SSDs in slot numbers 4 and 5. You can add the SSDs in a running system.Note:Make sure that the SSDs are NetScaler certified.
4. In the Management Service, navigate toConfiguration > System > RAIDand thePhysical Drivestab. You would see the SSDs that you added.
5. Navigate to theLogical Drivetab and clickAdd.
6. In theCreate Logical Diskpage:
   1. In theFirst Slotdrop-down list, select 4.
   2. In theSecond Slotdrop-down list, select 5.

   3. ClickCreate.

      Note:In Management Service, the slot number begins with zero. So the slot numbering in Management Service differs from the slot numbering on the physical appliance.

The logical drive is created and is listed under theLogical Drive tab. Click the refresh icon to update the order of the logical drives.

Add a second logical drive on the SDX 22000 appliance

To add another logical drive, insert the SSDs in slot numbers 6 and 7. In theCreate Logical Diskpage, select 6 from theFirst Slotlist, and select 7 from theSecond Slotlist.

Replace a defective SSD drive with a blank SSD drive

To replace a defective SSD drive with a blank SSD drive:

1. Navigate toConfiguration > System > RAID.
2. On thePhysical Drivestab, select the defective drive that you want to replace.
3. ClickPrepare to Removeto remove the drive.
4. Click the refresh icon to refresh the list of physical drives.
5. Physically remove the defective drive from the slot.
6. Insert the new Citrix verified SSD in the slot from where you removed the defective SSD.
7. In the Management Service, navigate toConfiguration > System > RAID. The new SSD is listed in thePhysical Drivessection. The drive rebuild process starts automatically.

Click the refresh icon to check the status of the rebuild process. When the rebuild process is complete, you can see Online, Spun Up status in theFirmware Statecolumn.