Type
  • Best Practice
Description
  • This article explains the NetApp storage structure and how its specific characteristics can be merged into a common, vendor-agnostic architecture.
Additional Keywords
  • TrueSight Capacity Optimization

Related Topics

Knowledge Base

Understanding the NetApp Integration into BMC TrueSight Capacity Optimization

KB1170 - Jul 31, 2015

Objective

The terminology used in the ETLs developed by Sentry Software for BMC TrueSight Capacity Optimization has been standardized to cover all the different storage manufacturers’ concepts. As a result the terminology may differ from the storage vendor terminology. This is particularly true for the NetApp Data ONTAP ETL.

This article explains the NetApp storage structure and how its specific characteristics can be merged into a common, vendor-agnostic architecture.

The NetApp Storage Architecture

History

NetApp Fabric-Attached Storage (FAS) systems are historically dedicated to network attached storage (NAS) technologies. The storage architecture has initially been designed to serve files over network through NAS protocols such as Network File System (NFS), Common Internet File System (CIFS), File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), etc. The hardware and Data ONTAP operating system have been later improved to offer data-block storage features to enable Storage Area Network (SAN) protocols (Fiber Channel, FCoE, and iSCSI) to compete with disk array vendors.

Storage Distribution

NetApp Aggregate

NetApp Aggregate is the initial layer of storage in NetApp. An Aggregate is a RAID-level collection of disks. Aggregates provide storage to volumes. Aggregates can be composed of either disks through RAID-DP or Storage Volumes from the SAN, but not both. Data ONTAP organizes the disks or Storage Volumes in an Aggregate into one or more RAID groups. Aggregates are pools of storage.

NetApp Volume

NetApp Volumes are data containers or partitions of the Aggregate to serve files through NAS protocols supported by Data ONTAP (such as NFS, CIFS, HTTP, and WebDAV). NetApp Volumes form a file system. NetApp Volumes can be partitioned using qtrees that act like a folder hierarchy on a file system with additional features (quotas, oplocks, SnapVault, SnapMirror).

NetApp LUN

Block devices are then built on top of NetApp Volumes. These Logical Unit Number (LUN) devices are accessible through SAN protocols supported by Data ONTAP (FC, FCoE, iSCSI, etc.). Concretely, NetApp LUNs are files available in the file system (NetApp Volume).

Differences with Disk Arrays

The following diagram compares the storage structure between a regular Disk Array and the NetApp system:

NetApp has a completely different architecture for storage components:

  • In Disk Arrays, block devices (Storage Volumes) are created in Storage Pools. Then file-serving features (or Storage Shares) are provided by adding a file-system to the volumes and exposing them through a filer.
  • In NetApp, file-systems (NetApp Volumes) are created in Aggregates. Block devices (NetApp LUNs) are then provided from the file-systems. NetApp LUNs are actually files.

Another difference is the terminology used. Generally to refer to a block device, Volume is preferred over LUN, as LUN defines an identifier on the SAN and can be bound to more than one block device. Many vendors expose internal block devices as volumes to manage features such as thin provisioning pools extension, snapshots, replication, etc. NetApp uses the term volume for the file systems created in the aggregate and shared on the network through NAS protocols. This naming conflict can be confusing when comparing storage attributes.

NetApp ETL for BMC TrueSight Capacity Optimization

Discovery

The NetApp Data ONTAP ETL developed by Sentry Software discovers the following hardware and logical components from the NetApp systems:

  • Controllers (or Nodes in Cluster Mode)
  • Ports
  • Disks
  • vFilers (or Vservers in Cluster Mode)
  • Aggregates
  • Volumes
  • LUNs

All these components are grouped under a Storage System that represents the actual HA Pair (or Cluster).

Entities Created

The NetApp components discovered are created as entities in TrueSight CO. Hardware components (Controllers or Nodes, Ports, and Disks) are imported as sub-objects consolidated in the storage system entity. Logical components dedicated to storage are created using either the Storage –Vendor Agnostic or the NetApp Specific Terminology:

NetApp Component Storage - Vendor Agnostic NetApp Specific Terminology
HA Pair Storage System NetApp HA Pair
Cluster Storage System NetApp Cluster
vFiler Storage Filer NetApp vFiler
Vserver Storage Filer NetApp Vserver
Aggregate Storage Pool NetApp Aggregate
Volume Storage Share NetApp Volume
LUN Storage Volume NetApp LUN
Note: The Entity Type to be used can be set while configuring your NetApp Data ONTAP ETL. For more information, refer to the user documentation.

We recommend keeping the default Storage - Vendor Agnostic option selected to make the ETL compatible with the Storage Views or to be able to compare multiple SAN vendors without confusion about the terminology (specifically NetApp volumes that are not block devices).

The NetApp-Specific Terminology option should be preferred if you plan to only use the NetApp Data ONTAP ETL or need to provide specific reports usingp the NetApp terminology.

Here are definitions about the entity types used:

Storage System

This entity type represents the whole system including hardware resources. The Storage System displays consolidated capacity and performance metrics and per resource metrics on controllers, ports and disks such as CPU utilization, IOPs, transfer rates and various other metrics...
NetApp HA Pair (when using 7-Mode) or NetApp Cluster (when using Cluster Mode) will be mapped to the Storage System entity type.

Storage Filer

A filer is a logical component that represents a NAS server. The filer will expose shares through NAS protocols.
NetApp vFiler (when using 7-Mode) or NetApp Vserver (when using Cluster Mode) will be mapped to the Storage Filer entity type.

Storage Pool

A storage pool is a logical component that provides consolidated (or distributed) space for storage administrators.
NetApp Aggregate will be mapped to the Storage Pool entity type.

Storage Share

A share is a logical device that represents a file system exposed in a NAS network.
NetApp Volume will be mapped to the Storage Share entity type.

Storage Volume

A volume is a logical device that represents a block level data container (or block device) exposed in a SAN.
NetApp LUN will be mapped to the Storage Volume entity type.

Hierarchy and Relations

Hierarchy

Depending on the “Entity Types” configured, the hierarchy tree will differ but all the entities and relations will remain same.

  Storage - Vendor Agnostic NetApp Specific Terminology
NetApp 7-Mode inline inline
NetApp Cluster-Mode inline inline

Relations Created

Relation between Storage - Vendor Agnostic NetApp Specific Terminology
Aggregate and the storage system SA_CONTAINS_SP NETAPP_CONTAINS_AGGREGATE
NetApp LUN and the storage system SA_CONTAINS_VOLUME NETAPP_CONTAINS_LUN*
NetApp Volume and the storage system SA_CONTAINS_SHARE* NETAPP_CONTAINS_VOLUME*
NetApp vFiler/Vserver and the system SA_CONTAINS_FILER NETAPP_CONTAINS_FILER
NetApp Volume and the vFiler/Vserver FILER_CONTAINS_SHARE FILER_CONTAINS_VOLUME
Aggregate and the vFiler/Vserver FILER_CONTAINS_SP* FILER_CONTAINS_AGGREGATE*
NetApp LUN and the vFiler/Vserver FILER_CONTAINS_VOLUME* FILER_CONTAINS_LUN*
NetApp LUN and the Aggregate SP_CONTAINS_VOLUME* AGGREGATE_CONTAINS_LUN*
NetApp Volume and the Aggregate SP_CONTAINS_SHARE AGGREGATE_CONTAINS_VOLUME
NetApp LUN and the NetApp Volume SHARE_CONTAINS_VOLUME VOLUME_CONTAINS_LUN
* Relation is not displayed in the workspace hierarchy tree but is accessible  through the ‘Hierarchy’ tab of the entities.