NetApp FAS

ONTAP is NetApp's internal operating system, specially optimized for storage functions at high and low levels.

All NetApp ONTAP-based hardware appliances have battery-backed non-volatile random access memory or NVDIMM, referred to as NVRAM or NVDIMM,[citation needed] which allows them to commit writes to stable storage more quickly than traditional systems with only volatile memory.

Modern NetApp FAS, AFF or ASA system consist of customized computers with Intel processors using PCI.

Each FAS, AFF or ASA system has non-volatile random access memory, called NVRAM, in the form of a proprietary PCI NVRAM adapter or NVDIMM-based memory, to log all writes for performance and to play the data log forward in the event of an unplanned shutdown.

Each storage system model comes with a set configuration of processor, RAM, and non-volatile memory, which users cannot expand after purchase.

With the exception of some of the entry point storage controllers, the NetApp FAS, ASA, and AFF systems usually have at least one PCIe-based slot available for additional network, tape and/or disk connections.

Also, AFF systems do not support FlexArray with third-party storage array virtualization functionality.

AFF & FAS use the same firmware image, and nearly all noticeable functionality for the end-user is the same for both storage systems.

ASA is the same as AFF, and the only difference is in the access to the storage over the network with SAN protocols: ASA provides symmetric active/active access to the block devices (LUN or NVMe namespaces), while Unified ONTAP systems continue to use ALUA and ANA for the block protocols.

[3] In February 2023, NetApp introduced a new AFF product line code named the C-Series.

This platform uses quad-level cell (QLC) NAND flash and is aimed at competing with the QLC-based products already in the market from Pure Storage (specifically FlashArray//C).

However, the aim of the platform is to provide a lower price point for customers that might otherwise not choose all-flash systems.

[5] Physical HDD and SSD drives, partitions on them, and LUNs imported from third-party arrays with FlexArray functionality considered in ONTAP as a Disk.

This technique mainly used to overcome some architectural requirements and reduce the number of disk drives in ONTAP-based systems.

NetApp overcomes the write performance penalty of traditional RAID-4 style dedicated parity disks via WAFL and a novel use of its nonvolatile memory (NVRAM) within each storage system.

Each RAID group usually consists of disk drives of same type, speed, geometry and capacity.

Though NetApp Support could allow a user to install a drive to a RAID group with same or bigger size and different type, speed and geometry for temporary basis.

Within aggregates, ONTAP sets up flexible volumes (FlexVol) to store data that users can access.

Also, in NetApp FAS systems with FlexArray feature, the third-party LUNs could be combined in a Plex similarly to RAID 0.

NetApp storage systems running ONTAP can be deployed in MetroCluster and SyncMirror configurations, which are using technique comparably to RAID 1 with mirroring data between two plexes in an aggregate.

NetApp Storage Encryption (NSE) is using specialized purpose build disks with low level Hardware-based full disk encryption (FDE/SED) feature and also supports FIPS-certified self-encrypted drives, compatible nearly with all NetApp ONTAP features and protocols but does not offer MetroCluster.

[9] MetroCluster (MC) is free functionality for FAS and AFF systems for metro high availability with synchronous replication between two sites, this configuration requires additional equipment.

MetroCluster configurations are possible only with mid-range and high-end models which provide the ability to install additional network cards required to MC to function.

FAS and AFF systems with ONTAP software versions 9.2 and older utilize FC-VI cards and for long distances require 4 dedicated Fibre Channel switches (2 on each site) and 2 FC-SAS bridges per each disk shelf stack, thus minimum 4 total for 2 sites and minimum 2 dark fiber ISL links with optional DWDMs for long distances.

Starting with ONTAP 9.3 MetroCluster over IP (MCC-IP) was introduced with no need for a dedicated back-end Fibre Channel switches, FC-SAS bridges and dedicated dark fiber ISL which previously were needed for a MetroCluster configuration.

MetroCluster over IP require Ethernet cluster switches with installed ISL and utilize iWARP cards in each storage controller for synchronous replication.

ONTAP OS provides enterprise level data management features like FlexClone, SnapMirror, SnapLock, MetroCluster etc., most of them snapshot-based WAFL File System capabilities.

It is possible to switch between modes on a FAS system but all the data on disks must be destroyed first since WAFL is not compatible and server-based application called 7MTT tool was introduced to migrate data from old 7-mode FAS system to new Cluster-Mode: Additional to 7MTT there are two other paths to migrate data based on protocol type: Before the release of ONTAP 8, individual aggregate sizes were limited to a maximum of 2 TB for FAS250 models and 16 TB for all other models.