Announcing IBM Scale Out NAS (SONAS)
IBM recently announced a new Scale Out NAS solution based on their General Parallel File System (GPFS). IBM’s SONAS bundles together GPFS with NFS and CIFS interface software together with interface, storage and management hardware nodes in a file system cluster to produce a scalable NAS solution.
SONAS hardware architecture
Management, interface and storage nodes are all X3650 servers. All hardware nodes are cross-connected with a 20Gbps infiniband, low latency interconnect. Each SONAS has at least two interface nodes, two storage nodes, and one management node.
- · Interface nodes – all file services meta-data (directories) are spread across all interface nodes. As such, files can be accessed from any host connected to an interface node and workloads can be balanced across interface nodes. Each interface node can support both GigE as well as 10GbE host connection.
- Storage nodes – backend data resides on storage pods and is accessed via storage nodes. Each storage pod has one or two storage controllers with a 4U tall, 60-disks enclosures and can have 1 or 2 additional expansions units with 60 disks each. The interface between the storage node and the storage controllers is direct FC attach. Storage pods support both SATA and SAS disk drives.
- Management node – provides performance, availability and system health monitoring services for the cluster and also supports a GUI management console. In addition, the management node can be used to specify automated policy management for files in SONAS.
IBM didn’t state any architectural limitations for SONAS but they plan to sell two appliance configurations. Specifically, a
- Single rack system appliance with 2 to 6 interface nodes, 2 storage nodes, and up to 240 drives
- Multi-rack extensions supporting up to 30 interface nodes and up to 30 storage pods for a maximum of 7,200 drives.
As such, the maximum configuration, using 1TB drives, can scale up to 7.2PB and with 2TB drives in 2Q10, over 14PB of file storage.
SONAS Software architecture
As you may recall, IBM’s GPFS was a clustered file system supporting parallel file system access. IBM’s Global Technology Services has installed GPFS in a number of high profile institutions and it continues to be available as a software only product. But pure GPFS requires running the GPFS file system client services and does not inherently support CIFS or NFS interfaces. What SONAS has done is to provide a number of interfaces and a hardware packaging that make GPFS functionality more accessible to most mainstream users.
SONAS’s GPFS implementation runs on Linux O/S. Also, SONAS supports up to 256 file systems and can take up to 256 snapshots per file system. Current file interfaces supported include NFS, CIFS and FTP and plans are to support HTTPS and SCP (Secure Copy) in future releases. Also, SONAS contains a cluster trivial database (CTDB) to speed up SAMBA or CIFS operations.
In addition, SONAS supports interface node level resident backup software clients (first from IBM) and replication management. Backups executing on a SONAS interface node should significantly outperform any host system backup and today supports Tivoli Storage Manager (TSM) backup with other vendor backup coming available in the future. Future SONAS systems will support HSM client services using an external TSM server to provide ILM-like services for file data. Currently, SONAS policy management provides for intelligent file placement into user specified storage pools. In the near future, asynchronous replication at the file level will be available.
IDC forecasts that file based data is growing at a 60.1% CAGR. Significantly though, most of this growth happens after 2010.
Specific verticals IBM is targeting for SONAS include Media & Entertainment, Aerospace & Defense, Retail Banking & Financial Markets, Automotive, Chemical & Petroleum, Government and Healthcare. While most of these are certainly understandable, retail banking and healthcare may be a bit of a stretch for SONAS.
IBM’s SONAS is a good addition for high-end file serving but it seems to be at the extreme end of the market. Most other vendors, including IBM’s own N-Series with Spinnaker integration into ONTAP are all focused on 2 to 8 node file system clusters, significantly smaller than SONAS’s top end.
However, HP’s acquisition of Ibrix, Dell’s purchase of ExaStore, the continuing existence of Panasas, Isilon and Symantec’s FileStore, as well as the recent startup Avere Systems all seem to imply some believe there is a serious market for high-end file services. Which of these are cluster and which scale out file systems are subject to some debate in the industry. Nevertheless, the market will ultimately decide which of these succeed and has a future in tomorrow’s storage environment.
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Silverton Consulting, Inc. is a Storage, Strategy & Systems consulting services company, based in the USA offering products and services to the data storage community.
 Source: IDC, State of File-Based Storage Use in Organizations: Results from IDC’s 2009 Trends in File-Based Storage Survey, Doc # 221138, December 2009