NAS Backup Or San Backup – Which Suits Best?

by Rod Dunne on July 28, 2010

in Backup Software, Data Recovery

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Storage systems within companies are increasingly needing to store massive volumes of system data, which makes the choice of storage and backup solution (NAS or SAN backup) a key consideration in a disaster recovery plan.

Here, we’ll look at the main criteria to consider for choosing between a SAN or NAS backup solution based on key business goals.

Capacity

The first consideration is the amount and type of data being stored and shared. NAS solutions were designed for providing storage and serving files across a network, to alleviate servers of this strain. SAN solutions work at volumes high above simple file sharing by facilitating large data block sharing over fibre channels between servers/devices.

If the volume of data being transferred is low then the standardized network protocols (TCP/IP, FC and CIFS) used in NAS solutions may suffice (for example, for NAS tape backup tasks were the process may only run during downtime).

Performance

Real time systems that require high I/O speeds of data will be best suited to use with SAN systems with their fibre channel high-speeds. Any file transfer processes that do not require the same throughput should avail of NAS storage.

Scalability

Each company has their own projected data-growth expectations. As storage demands increase, then so too do network demands and backup requirements.

NAS solutions provide terabytes of data storage using (mainly) disk drive technology which is cost-effective and the devices can easily be clustered/augmented with additional storage. Providing a backup to NAS devices should be quite scalable thanks to the ease of connecting additional devices. Multiple operating platforms can also be supported.

A SAN network is equally scalable but is generally tied to supporting a single platform and adding new devices can prove more complex to setup and administer than NAS storage.

Reliability And Availability

This is the key differentiator between the two approaches. SAN systems were designed from the outset with a distributed architecture to provide reliable access to data, data mirroring, fast data access and dynamic load balancing.

This makes them ideal for systems requiring simultaneous data access by large volumes of users.

Some NAS backup and storage solutions can support mirroring and replication but they generally cannot compete with the fast I/O access speeds seen on a SAN.

Data Recovery And Protection

Both approaches can incorporate multiple computer backup options and systems. Doing a backup to NAS disks is standard practice given the volume of disk storage that is available, but it is still worth integrating a NAS tape backup machine as a secondary system (backups can then be stored in offsite tape storage facilities).

SAN systems can also connect backup devices to their hub/switch along with remote servers for easy duplication (business continuance).  Any backup to NAS storage devices will be inherently slower than on the SAN fibre – this turnaround time for recovering systems will be a major constraint in the company’s disaster recovery plan.

Staffing

A NAS network is generally quite easy to setup (thanks to standardization of protocols) and easy to administer using software. A small team with general network administration skills can normally handle the NAS backup/support requirements.

A SAN architecture is altogether more complex, incorporating more servers/devices that need to be integrated into the system. A SAN is intended for high-availability, high reliability enterprise solutions so they need more configuration to setup and more operational administration and monitoring by specialized staff.

Cost concerns

NAS solutions are generally cheaper to buy, install and run. The devices use disk drive technology which gets cheaper and faster with each year.

The use of SAN solutions requires high-level devices, networks and hardware to support the volume of data transfers of mission critical systems. And all these come at a cost.

Many companies combine the two solutions to make a cost effective approach, using NAS tape backup and storage for low volume file transfers and only using SAN on real-time high availability systems.

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