vRanger 7.8.1 - Integration Guide for NetVault SmartDisk

Choosing a deployment location for a NetVault SmartDisk Instance

Choosing a deployment location for a NetVault SmartDisk Instance

The third step in defining your NetVault SmartDisk Deployment Strategy is deciding where you want to deploy your NetVault SmartDisk Instances. Whether the NetVault SmartDisk Instance is enabled for deduplication dictates the available deployment options.

Reviewing deployment options for NetVault SmartDisk Deduplicated Instances

Reviewing deployment options for NetVault SmartDisk Deduplicated Instances

Multiple vRanger servers cannot target the same repository. For this reason, in environments with one or more vRanger servers, you must deploy a NetVault SmartDisk Instance for each vRanger server.

 

NOTE: You cannot deploy multiple NetVault SmartDisk Instances on the same machine.

Defining a NetVault SmartDisk Storage Pool strategy

Defining a NetVault SmartDisk Storage Pool strategy

The fourth step in defining your NetVault SmartDisk Deployment Strategy is defining your strategy for the NetVault SmartDisk Storage Pools.

Understanding space allocation for NetVault SmartDisk Storage Pools

Understanding space allocation for NetVault SmartDisk Storage Pools

Before choosing a strategy for your NetVault SmartDisk Storage Pools, consider the following regarding how NetVault SmartDisk allocates space in the NetVault SmartDisk Storage Pools:

•	You can add an unlimited number of Storage Pools to NetVault SmartDisk.

•	You can add an unlimited number of volumes to each NetVault SmartDisk Storage Pool.

•	Each NetVault SmartDisk Storage Pool is associated with roles that it can perform.

•	When configuring a NetVault SmartDisk Storage Pool, you can identify it as a favorite for specific roles (favour), and you can indicate that it should never be used for specific roles (deny).

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There is no quota specified per-volume of the absolute amount of space NetVault SmartDisk can use; that is, you cannot say “use exactly 100 GB.” However, you can specify an amount of physical disk-storage that you want to set aside that NetVault SmartDisk cannot use. This option simplifies the NetVault SmartDisk internal space-allocation policies so that Staging Store and Chunk Store processes can efficiently share volumes. Each role independently implements and honors the configured thresholds, which allows efficient parallel-processing without a requiring a single, centralized space allocator.

•	Using the volume-size parameter, you can set aside a portion of the volume so that it cannot be used for NetVault SmartDisk. After the volume is full with NetVault SmartDisk or non-NetVault SmartDisk data, NetVault SmartDisk does not store anything else on the volume until space is made available.

•	NetVault SmartDisk uses storage space in each volume up to a threshold amount that includes space directly set aside using the volume-size parameter, and the Last Resort Threshold (LRT) amount set by NetVault SmartDisk internally.

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NetVault SmartDisk first uses a volume for its intended role, for example, Chunk Store or Staging Store, but it also uses it for other purposes if necessary. Even if you supply a threshold, NetVault SmartDisk implements an LRT that stops NetVault SmartDisk from using a volume after there is less than a certain amount of space available and thus prevents the disk from becoming full. The LRT is calculated to include both a fixed amount of space (1 GB) and the space that would be required to make Garbage Collection possible, that is, the gc_reserve_bytes parameter. This process means that the figure varies in size depending on the amount of data held in the Chunk Store; typically, you can expect the gc_reserve_bytes parameter to be at least 1.7 GB.

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If the LRT is large enough, NetVault SmartDisk properly allocates space when multiple Staging Store and Chunk Store processes are both writing to a volume that becomes too full. NetVault SmartDisk maintains an overall idea of how much space is used both by the Staging Store and the Chunk Store. This allows it to enforce the licensed amount of capacity and to enforce the LRT and the volume-size limits.

•	User thresholds and the NetVault SmartDisk LRT do not affect licensing. Licensing measures the amount of data accepted for protection by the NetVault SmartDisk Instance, regardless of whether the data has been deduplicated.

The following figure shows a graphical example of how space is organized in NetVault SmartDisk. This figure assumes that all volumes are mapped to one file system. Also, the space reserved for LRT is reserved on a per-volume basis; if your configuration uses multiple volumes, more LRT space might be allocated.

Figure 1. Space allocation for NetVault SmartDisk