SAN (Storage Area Network) and NAS (Network Attached Storage) are two common types of networked storage systems used by businesses and organizations to store and access data. While they have some similarities, there are important differences between SAN and NAS that impact how and where they are used.
What is a SAN?
A SAN is a dedicated high-speed network used to connect servers and shared pools of storage devices. The key components of a SAN include:
- Storage devices – Such as disk arrays, tape libraries, and optical drives
- SAN switch – Device that connects servers to storage devices
- Cables – Fiber channel cables are commonly used to connect devices
SANs use special networking protocols like Fibre Channel and iSCSI to enable very fast data transfers and access. SAN hardware and software create a pool of storage that can be accessed by any authorized server on the network. Because a SAN is a distinct network, it does not impact bandwidth on the main local area network (LAN).
Advantages of SANs
- Very fast data transfers and low latency
- Centralized storage leads to easier management
- Highly scalable to meet storage growth
- Data is accessibile from different servers
- Data is securely isolated from main LAN
Disadvantages of SANs
- More complex and expensive to implement and manage
- Require specialized hardware, software, and training
- Single point of failure unless redundancies are built in
What is NAS?
NAS or Network Attached Storage is file-level storage that connects to a local area network (LAN) to provide shared storage and file access for authorized users and systems. The key components of a NAS include:
- NAS device – Hardware appliance with CPU, RAM, storage drives, network interface, operating system
- Storage drives – Hard disk drives or solid state drives built into the NAS or attached externally
- Network interface – Ethernet port to connect to the LAN
- Operating system – Customized OS that manages file sharing and security
Users connect to NAS systems using network protocols like SMB, NFS, FTP or HTTP to store and retrieve data. Many NAS devices run specialized optimized operating systems. Consumer NAS devices are plug and play requiring minimal setup while business NAS devices offer more advanced configurations.
Advantages of NAS
- Easy to deploy since they connect directly to a LAN
- Many consumer models are low cost and plug and play
- Easier to scale capacity
- Files can be accessed by multiple users and systems
Disadvantages of NAS
- Performance can suffer in high-traffic environments
- Data is not isolated from main network which poses security risks
- Managing multiple NAS devices adds complexity
- Lack redundancy of SAN architectures
SAN vs NAS Comparison
While SAN and NAS provide shared storage, they are suited for different use cases. Here is a side-by-side comparison:
| Category | SAN | NAS |
|---|---|---|
| Network | Dedicated high-speed network (Fibre Channel, iSCSI, etc) | Standard local area network (Ethernet) |
| Architecture | Provides block-level storage to servers | Provides file-level storage over network |
| Scalability | Very high, specialized components | Limited by consumer-grade NAS systems |
| Speed | Very fast, optimized for throughput | Slower speeds, traffic shared with LAN |
| Complexity | Complex setup and management | Easy plug and play deployment |
| Data Security | Isolated so highly secure | Less secure since uses main network |
| Cost | More expensive for hardware and software | Low cost NAS appliances widely available |
| Use Cases | Mission-critical applications, large databases | Home office file sharing, departmental storage |
When to Use SAN vs NAS
With their distinct architectures, SAN and NAS are suited for different use cases:
- SAN – Use for mission-critical enterprise applications that require very high performance, scalability, and data security. Common SAN use cases include databases, ERP systems, CRM systems, VDI, and server virtualization.
- NAS – Use for departmental file shares, email storage, shared folders for collaboration, and general purpose file storage and backup. NAS provides good performance for less critical data at low cost.
Organizations often leverage both SAN and NAS technologies together to build a comprehensive storage infrastructure.
SAN Use Cases
Here are some examples of enterprise applications where a SAN provides the required performance and reliability:
- Databases – Databases need very fast access to their storage to ensure fast queries and transaction processing. A SAN provides low latency disk I/O perfect for large database workloads.
- Virtual desktop infrastructure (VDI) – In a VDI environment, a SAN stores the desktop images for each virtual machine being delivered to end users. The fast block-level access makes boot storms manageable.
- Big data analytics – Big data platforms like Hadoop rely on parallel processing across many servers requiring very fast data access. SAN delivers the speed and scalability big data needs.
- Email servers – For high volume enterprise email with thousands of users, SAN provides the scalability and reliability needed for the large email storage requirements.
NAS Use Cases
Here are some examples of where NAS makes sense for more general storage needs:
- File sharing – NAS excels at making files available over the network for collaboration and workflow. Multi-user access and simplicity make NAS ideal for this.
- Backups – Storing backup images requires large amounts of storage. NAS presents a cost-effective scalable platform for backups.
- Media storage – Video and graphics files can be substantial in size. Media teams can use NAS for the large shared storage these files require.
- Website hosting – Websites comprise many files accessible over HTTP. NAS appliances can provide simple cost-effective storage for hosting websites.
Conclusion
SAN and NAS provide organizations with options for shared storage connectivity that are optimized for different purposes. SAN excels at high performance block level storage while NAS is oriented to easy file sharing. Knowing the core distinctions allows architects to pick the right networked storage solution for the job.
With the advance of high speed Ethernet, there is growing convergence of SAN and NAS capabilities on unified storage platforms. But as standalone solutions, they each have ideal uses cases. A typical strategy is to deploy SAN for mission critical applications and NAS for file sharing roles.
By leveraging both SAN and NAS capabilities together, IT organizations can build comprehensive storage infrastructures tailored to the performance, security and accessibility needs of different applications and workgroups.