There are at least three different ways to provide file services for most IT environments:
- Use direct attached storage (DAS) disks or SSDs and map a file system on top of them using host operating system (O/S) software;
- Use Storage Area Network (SAN) iSCSI, FC or FCoE storage and map a file system on top of block LUNs using host operating system (O/S) software; or
- Use standalone, Network Attached Storage (NAS) systems that can support multiple file systems and can provide shared file storage across multiple hosts.
This Buying Guide focuses on NAS storage systems, for block LUN storage please see our SAN Storage Buying Guide. There are five types of NAS systems used for shared file data: NAS gateways, Integrated NAS solutions, Cluster-Parallel file systems, NAS accelerators and wide area file services (WAFS).
- NAS gateways and integrated NAS storage systems are very similar in data services and represent the more traditional networked file storage approach, available from just about all the major storage vendors, and support from small to enterprise class environments.
- Cluster and/or parallel file systems offer highly scalable storage for high performance and multi-PB file system needs but may require client software and may not support all O/Ss or all file interface protocols.
- NAS accelerators, caching appliances or aggregators systems offer a single management point for multiple NAS systems but can also provide dramatically increased performance for file data using external NAS storage behind it.
- Wide area file services (WAFS) extend file system access to remote locations connected to a central site, presenting a single image of NAS file data to all remote and central sites. NAS systems are typically accessed using one of two different storage protocols: NFS or SMB (formerly called CIFS for SMB1, AKA SMB2 or SMB3). Most Windows environments use SMB access protocols while Unix/Linux systems use NFS, but often both protocols can be used by the same host.
Some advanced file storage capabilities (see Features below) to look for in vendor NAS storage include: snapshot or point-in-time copies of file data; data reduction; and remote data mirroring/replication. Finally, as data centers consolidate more file data onto fewer NAS systems, high performance flash storage, high availability/fault tolerance, and non-disruptive upgrades should all be critical considerations.
A few new capabilities in the file storage space have recently emerged:
- File analytics - this provides statistical and other information about file data;
- Cloud file services/tiering services - this supplies file or archive services for specific public cloud storage providers; and
- Object storage support - this supports native object storage interfaces and file access protocols to the same storage.
The remainder of this Buying Guide describes the various NAS products in detail, discusses NAS storage features and functionality as well as NAS system performance providing several performance rankings for NAS storage systems. For example, in the NAS System Features tables below we identify feature availability and comparisons for over 40 current NAS product offerings from major vendors and in the NAS performance section we analyze NAS benchmark results ranking top NAS system performance using our NFS and SMB ChampionsCharts™ as well as provide top 20 NAS system performance charts for other performance metrics.
1.0 Executive Summary
2.0 NAS Product Types
2.1 NAS Gateways
2.2 Integrated NAS Systems
2.3 Cluster, Scale-Out Or Parallel File Systems
2.4 NAS Accelerators, Caching Appliances Or Aggregators
2.5 Wide Area File Services
3.0 NAS System Features
3.1 NFS And Smb Access Protocol Support
3.2 Object Storage Protocol Support
3.3 File Size And File System Size
3.4 High Availability
3.5 Storage Space Efficiency
3.6 Point-In-Time (P-I-T) Or Snapshot Copies
3.7 File System/Volume Copy
3.8 Volume Or File System Clones
3.9 File System Or Volume Extension
3.10 Quality Of Service (QOS)
3.11 Quota Data Management/Controls
3.12 Global Name Space
3.13 Network Data Management Protocol (NDMP) Support
3.14 Remote Mirroring Or Data Replication
3.15 Data Security
3.17 File Analytics
3.18 Data Migration
3.19 Cloud Storage Tiering
3.20 Automated Storage Tiering
3.21 Flash Cache
3.22 All-Flash Array (Afa) Storage
3.23 Direct IO
3.24 Unified Storage Or Block I/O Support
3.25 Multi-Tenancy Or Partitioning
4.0 NAS Feature Tables
5.0 NAS Performance
5.1 NFS Performance
5.2 Smb Performance
5.3 NFS Vs. CIFS/SMB Performance
5.4 SPEC SFS2014 Performance Results
LIST OF FIGURES
Figure 1 Traditional NAS Product Features
Figure 2 Cluster/Scale-Out File Systems
Figure 3 SCI NFS ChampionsChart™
Figure 4 SCI NFS NAS Aggregators ChampionsChart
Figure 5 Top 20 NFS throughput/disk spindle
Figure 6 Top 20 NFS Overall Response Time (ORT) results
Figure 7 Top 20 NFS throughput results
Figure 8 Top NFS throughput ops per node performance
Figure 9 SMB/CIFS ChampionsChart
Figure 10 Top CIFS/SMB Throughput ops/sec/disk
Figure 11 Top 20 CIFS/SMB ORT
Figure 12 Top 20 CIFS/SMB throughput operations per second
Figure 13 NFS vs. SMB throughput ops/disk scatter comparison
Figure 14 NFS vs. SMB throughput operations performance comparison for same hardware
Figure 15 NFS vs. SMB ORT comparison
Figure 16 SPEC sfs2014_VDA Maximum Streams
Figure 17 SPEC sfs2014_swbuild Maximum Builds
Figure 18 SPEC sfs2018_swbuild top 10 ORT