Wednesday, 5 October 2011


Network Appliance (NetApp)

This section is short introduction into Network Appliance (NetApp).


NetApp was created in 1992 by David Hitz, James Lau and Michael Malcolm, the company become public in 1995 and grew rapidly in the dot com boom, the companies headquarters are in SunnyvaleCaliforniaUS. NetApp has acquired a number of companies that helped in development of various products. The first NetApp network appliance shipped in 1993 known as a filer, this product was a new beginning in data storage architecture, the device did one task and it did it extremely well. NetApp made sure that the device was fully compatible to use industry standard hardware rather than specialized hardware. Today's NetApp products cater for small, medium and large size corporations and can be found in many blue-chip companies.

NetApp Filers can offer the following

•           Supports SAN, NAS, FC, SATA, iSCSI, FCoE and Ethernet all on the same platform
•           Supports either SATA, FC and SAS disk drives
•           Supports block protocols such as ISCSI, Fibre Channel and AoE
•           Supports file protocols such as NFS, CIFS , FTP, TFTP and HTTP
•           High availability
•           Easy Management
•           Scalable

NetApp Filer

The NetApp Filer also know as NetApp Fabric-Attached Storage (FAS), is a data storage device, it can act as a SAN or as a NAS, it serves storage over a network using either file-based or block-based protocols

File-Based Protocol     :  NFS, CIFS, FTP, TFTP, HTTP

Block-Based Protocol :  Fibre Channel (FC), Fibre channel over Ethernet (FCoE), Internet SCSI (iSCSI)

The most common NetAPP configuration consists of a filer (also known as a controller or head node) and disk enclosures (also known as shelves), the disk enclosures are connected by FC or parallel/serial ATA, the filer is then accessed by other Linux, Unix or Window servers via a network (Ethernet or FC). An example setup would be like the one in the diagram below

Filer Back view

The filers run NetApp's own adapted operating system (based on FreeBSD) called Data ONTAP, it is highly tuned for storage-serving purposes.

All filers have a battery-backed NVRAM, which allows them to commit writes to stable storage quickly, without waiting on the disks.

It is also possible to cluster filers to create a highly-availability cluster with a private high-speed link using either FC or InfiniBand, clusters can then be grouped together under a single namespace when running in the cluster mode of the Data ONTAP 8 operating system.

The filer will be either Intel or AMD processor based computer using PCI, each filer will have a battery-backed NVRAM adaptor to log all writes for performance and to replay in the event of a server crash. The Data ONTAP operating system implements a single proprietary file-system called WAFL (Write Anywhere File Layout).

WAFL is not a filesystem in the traditional sense, but a file layout that supports very large high-performance RAID arrays (up to 100TB), it provides mechanisms that enable a variety of filesystems and technologies that want to access disk blocks. WAFL also offers

  • snapshots (up to 255 per volume can be made)
  • snapmirror (disk replication)
  • syncmirror (mirror RAID arrays for extra resilience, can be mirrored up to 100km away)
  • snaplock (Write once read many, data cannot be deleted until its retention period has been reached)
  • read-only copies of the file system
  • read-write snapshots called FlexClone
  • ACL's
NetApp Backups

The last point to touch on is backups, NetApp offers two types

  • backs up files and directories 
  • supports level-0, incremental and differential backups 
  • supports single file restore 
  • capable of backing only the base snapshot copy 


  • Backs up blocks of data to tape 
  • Supports only level-0 backup 
  • does not support single file restore 
  • capable of backing up multiple snapshot copies in a volume 
  • does not support remote tape backups and restores 

The filer will support either SCSI or Fibre channel (FC) tape drives and can have a maximum of 64 mixed tape devices attached to a single storage system.

Network Data Management Protocol (NDMP) is a standardized protocol for controlling backup, recovery and other transfers of data between primary and secondary storage devices such as storage systems and tape libraries. This removes the need for transporting the data through the backup server itself, thus enhancing speed and removing load from the backup server. By enabling NDMP support you enable that storage system to carry communications with the NDMP-enabled commercial network-attached backup application, it also provides low-level control of tape devices and medium changers. The advantages of NDMP are 
  • provide sophisticated scheduling of data protection across multiple storage systems
  • provide media management and tape inventory management services to eliminate tape handling during data protection operations
  • support data cataloging services that simplify the process of locating specific recovery data
  • supports multiple topology configurations, allowing sharing of secondary storage (tape library) resources through the use of three-way network data connections
  • supports security features to prevent or monitoring unauthorized use of NDMP connections

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