About LUN configuration

You configure block disk (Fibre Channel), Edge Local, and iSCSI logical unit numbers (LUNs) under Configure > Manage: LUNs.

Typically, block disk and iSCSI LUNs are used to store production data. They share the space in the blockstore cache of the associated Edges, and the data is continuously replicated and kept synchronized with the associated LUN in the data center. The Edge blockstore caches only the working set of data blocks for these LUNs; additional data is retrieved from the data center when needed.

Edge Local LUNs are used to store transient and temporary data. Local LUNs also use dedicated space in the blockstore cache of the associated Edges, but the data isn’t replicated to the data center LUNs. VMware VMs containing independent VMDKs from Edge Local LUNs/non-Riverbed datastores are included for protection. During backups, disks created on Edge Local LUNs and non-Riverbed datastores are excluded.

To configure storage arrays using Fibre Channel, the product leverages raw device mapping (RDM) functionality through VMware ESXi. To configure a Fibre Channel LUN, you must perform these tasks in the ESXi server where the product is deployed:

• Expose the Fibre Channel LUNs to the ESXi server.

• Assign the discovered Fibre Channel LUNs as raw device mappings.

• Ensure that NPIV is disabled.

You can then discover and configure the Fibre Channel LUN as a block-disk LUN in the Management Console. After configuring the block-disk LUN in the Management Console, you must return to the ESXi server to configure high availability for the new LUN:

• In ESXi, modify the storage group to which the LUN belongs to expose the LUN to both ESXi servers running the Core failover peers.

• Ensure that the LUN is raw-data mapped (RDM) to both Core appliances.

• Ensure that the SCSI bus number of the RDM LUN is the same on both ESXi servers.

Block-disk LUNs for Fibre Channel are distinct from iSCSI LUNs in several important ways:

• No MPIO configuration—There is no MPIO configuration for block-disk LUNs. Multipathing is instead performed by the ESXi system.

• No Volume Snapshot Service (VSS) snapshot support—While all other snapshot features are supported, Windows VSS is not.

• SCSI reservations—Not taken on block-disk LUNs.

• Additional HA configuration required—Configuring high availability for Core failover peers requires that each appliance be deployed on a separate ESXi system. Similarly, block-disk LUNs must be exposed to both systems.

• Maximum of 59 Fibre Channel LUNs per ESXi system—ESXi systems allow a maximum of four SCSI controllers. (Each controller supports a maximum of 15 SCSI devices. Therefore, a maximum of 60 Fibre Channel LUNs are supported per ESXi system. However, the Core uses one of the LUNs for OS boot disk, and hence only 59 LUNs are usable. When the Cores are in HA configuration with LUN filtering enabled, only 45 LUNs may be usable.)