By Philip Crocker, Director of EMEA Marketing, Isilon Systems.
Many organisations are facing a tremendous increase in the amounts of data needed to conduct everyday business. The growth of unstructured data such as video, audio, image, research data, and other large digital files is pushing the bounds of traditional storage systems. Into the breach come Clustered Storage and Storage Virtualisation to potentially offer solutions to help meet the challenge of larger data storage requirements.
So what is Clustered Storage?
Modern storage clustering has gone way past the simple fail over between a pair of redundant server/controller head and disks. Today, most advanced systems tend to be Distributed Clustered Storage. This architecture is a networked storage system that allows users to add self-contained nodes to continually expand the cluster. Each node contains processing power, cache, terabytes of disk storage and front and backend interconnect normally based on Gigabit Ethernet, InfiniBand or Fibre Channel.
Each node also has a suite of built-in applications to deliver the three layers of traditional storage architectures; file system, volume manager and RAID. This creates an intelligent fully symmetrical file system that spans all nodes within a cluster. This allows each node to serve any data file to any client irrespective of where the data physically resides on the cluster.
Strengths:
- Ability to scale performance and capacity independently
- High availability able to remain operational even with multiple simultaneous drive or node failures
- Highly automated management functions including load balancing, drive rebuilds, data replications.
- No independent interoperability standards between vendors
- Not suited to highly structured “small” files like email or database transactions
- Unable to virtualise existing NAS or SAN hardware
Storage virtualisation is essentially an aggregation technology that presents a single “virtual” storage infrastructure normally derived from different storage end points. These solutions vary greatly and are often a combination of software applications, appliances and switches to create a single namespace of storage that appears to management systems as one large pool of data. Typically, these solutions enable “synthetic trees” that encompass several NAS servers or storage devices. Most virtualisation solutions can control laying out a file (striping data) across disk volumes to a specific silo but often not across the silos that make up the virtualisation. The ability to categorise data makes virtualisation suitable for information lifecycle projects, as it will often allow data movement between tiers of storage with limited client interruption.
Strengths:
- Ability to tie together multiple storage vendor products under a single virtual namespace
- Prolongs the life of otherwise redundant storage platforms
- Reduces management overhead compared to traditional “islands” of storage
- Limited scalability for both capacity and performance
- Limitation on largest file size and largest single name space imposed by underlying NAS silos
- Increased complexity especially during drive or controller failures
Both technologies aim to reduce the cost of managing data and succeed in many respects. As an analogy, Clustered Storage is building an infrastructure from the ground up to deal with large files and huge volumes of data. Where as Storage Virtualisation is a short-term response to the problem of spiralling data management using tools to help alleviate the burden until organisations can take a pause and create a lasting fix.
The factors involved in each potential customer’s circumstances are too varied to make a clear-cut “winner” but a simple rule can be extrapolated for the casual observer. If an organisation wants to build a multi-terabyte capacity storage pool suitable for large capacity data files then clustered storage is a better option. If an organisation has invested in a lot of NAS and SAN hardware that is complex and expensive to manage then Storage Virtualisation offers the most immediate benefits. Depending on the situation, each technology can allow the customer to significantly improve their ability to manage data storage.
Isilon Systems is exhibiting at Storage Expo 2008 the UK’s definitive event for data storage, information and content management. Now in its 8th year, the show features a comprehensive FREE education programme and over 100 exhibitors at the National Hall, Olympia, London from 15 - 16 October 2008 www.storage-expo.com
Source: Eskenzi PR Ltd.
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