NetApp FAS

Lore & Background

Early FAS storage systems connected to external disk enclosures via parallel SCSI, while modern models use SCSI over Fibre Channel and SAS. The systems are built on customized computers with Intel processors using PCI, and include non-volatile random access memory (NVRAM) in the form of a proprietary PCI NVRAM adapter or NVDIMM-based memory to log all writes for performance and replay in the event of an unplanned shutdown. Implementers often organize two storage systems in a high-availability cluster with a private high-speed link, such as Fibre Channel, InfiniBand, or 10/40/100 Gigabit Ethernet.

Each storage system model comes with a set configuration of processor, RAM, and non-volatile memory that users cannot expand after purchase, though most have at least one PCIe-based slot for additional network, tape, or disk connections. In June 2008, NetApp announced the Performance Acceleration Module (PAM), an optional PCIe card providing additional cache between disk and system memory to optimize intensive random read workloads. FAS systems use enterprise-level HDD and SSD drives with two ports, each connected to one controller in an HA pair, and drives can only be bought from NetApp and installed in NetApp's Disk Shelves.

Reader's Guide

The NetApp FAS family represents a foundational product line in the ONTAP ecosystem, serving as a hybrid storage platform that balances capacity and cost through the combination of SAS SSDs and HDDs. Its significance lies in its role as the original hardware platform for Data ONTAP, the proprietary operating system with the WAFL file system designed specifically for storage-serving purposes. FAS systems are part of the broader Unified ONTAP architecture, capable of providing both NAS (via NFS, SMB, and S3) and SAN (via Fibre Channel, FCoE, iSCSI, and FC-NVMe) protocols. The legacy of FAS includes its influence on later all-flash variants (AFF and ASA), which share the same hardware platforms and firmware images but differ in internal data handling and write allocation algorithms. FAS systems continue to use ALUA for block protocols, distinguishing them from ASA systems that provide symmetric active/active access. The product line also introduced Advanced Drive Partitioning (ADP) techniques such as Root-Data partitioning to reduce the number of drives needed for system root aggregates.

Did You Know?

• FAS systems combine SAS SSDs and HDDs for a hybrid storage approach.
• FAS systems use battery-backed NVRAM or NVDIMM to commit writes quickly and replay logs after unplanned shutdowns.
• The Performance Acceleration Module (PAM) was announced in June 2008 to optimize random read workloads.