Certified - CompTIA Server+

Shared storage is a system design in which multiple servers access a single storage resource over a network. This architecture enables high availability, centralized backup, clustered applications, and efficient use of storage infrastructure. Shared storage eliminates the need to duplicate data across multiple machines and supports virtualization platforms and workload balancing. This certification includes shared storage concepts such as network attached storage and storage area networks, both of which are used extensively in modern server environments.
Networked storage architectures allow organizations to scale infrastructure while maintaining performance and reliability. By separating compute and storage functions, systems can grow independently. Shared storage reduces data duplication, simplifies maintenance, and supports remote access. It also enables disaster recovery planning and centralized management. Technicians must understand the structure, benefits, and limitations of shared storage systems to support clustered environments and high-availability solutions.
Network attached storage is a file-level storage system that connects to the network using standard Ethernet. NAS appliances provide shared folders that can be accessed by multiple clients using protocols such as the network file system for Linux or the common internet file system and server message block for Windows environments. NAS devices are self-contained and easy to deploy, requiring minimal infrastructure beyond basic network connectivity.
A storage area network provides block-level storage over a dedicated or converged network. SANs use specialized protocols such as Fibre Channel or internet small computer systems interface to transfer data. Unlike NAS, SAN storage appears to the host operating system as a local disk, allowing applications to use standard file systems and volume management. SANs require switches, host bus adapters, and precise configuration for reliable performance.
The core difference between NAS and SAN lies in how storage is presented. NAS operates at the file level, delivering shared folders through the network. SAN presents raw block devices that require the host to apply file systems and partition schemes. NAS is easier to set up and manage for small to mid-size networks. SANs are more complex but provide superior speed, flexibility, and control in enterprise deployments. This certification includes recognizing the protocol stack and performance tradeoffs.
NAS is often used for departmental file shares, home directories, and archives. It supports applications like media streaming and light-duty backup storage. NAS is valued for simplicity, affordability, and ease of scaling. In small and medium business environments, NAS may serve as the primary file server. Its use of standard protocols and IP networking makes it widely compatible and easy to integrate into existing infrastructures.
SANs support applications that require low latency and high throughput, including databases, virtual machines, and clustered systems. SANs can deliver storage to multiple hosts while maintaining performance isolation. Advanced features such as multipath input output, snapshots, and thin provisioning are typically available. SAN environments require careful design, including zoning, logical unit number mapping, and controller redundancy to maintain reliability.
Access control in shared storage varies by system type. NAS uses user-level authentication, often integrated with directory services such as active directory or lightweight directory access protocol. Permissions are applied to folders and files using access control lists. SANs control access at the hardware layer using world wide names for Fibre Channel or iSCSI qualified names for IP-based SANs. This distinction is important to prevent unauthorized access or data corruption.
High availability in shared storage is achieved by redundant paths and components. NAS systems may have dual network interfaces connected to separate switches. SANs use multiple host bus adapters or network interface cards to maintain connectivity if one path fails. Storage controllers, power supplies, and disks are also redundant in enterprise-grade systems. This certification includes configuring and maintaining multipath environments for resilience and failover capability.
File system considerations differ between NAS and SAN environments. NAS devices use internal file systems such as the Z file system, extended file system four, or new technology file system to manage their own volumes. Clients interact with these volumes at the file level. SAN volumes are formatted by the host operating system using the file system appropriate to the application. Compatibility between file system type and host operating system is essential for stability and performance.
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Many NAS and SAN systems offer snapshot and replication capabilities as part of their core feature set. A snapshot captures a point-in-time state of the data without interrupting access or requiring a service stop. Snapshots are used for backups, testing, or rapid rollback in case of data corruption. Replication allows data to be copied to another device or location for disaster recovery. Replicated volumes may reside off-site, in the cloud, or at a remote branch to protect against catastrophic failure.
Vendor lock-in and protocol compatibility are important considerations in shared storage environments. Some manufacturers implement proprietary hardware or management tools that limit integration with third-party systems. Open standards such as NFS, CIFS, or iSCSI help avoid lock-in by allowing interoperability with multiple platforms. This certification includes weighing the risks and benefits of vendor-specific features against long-term flexibility and support.
Multipathing is a design technique that provides fault tolerance and improved throughput by enabling multiple data paths between the host and storage. If one path fails, traffic can continue on the remaining path without service interruption. Load balancing uses these paths concurrently to distribute traffic, improving performance. Proper configuration of multipath daemons and input output policies ensures redundancy and optimal usage of available links. Server Plus includes awareness of multipathing as part of high-availability design.
Mounting shared storage varies between NAS and SAN systems. NAS volumes are mounted through network shares using host operating system commands. They may be accessed through UNC paths or mapped drives in graphical environments. SAN volumes appear as unformatted disks and must be initialized, partitioned, and formatted by the operating system. Proper mounting includes verifying permissions, mount order, and access restrictions to avoid data conflicts or application errors.
Backup integration with shared storage ensures data protection and fast recovery. Both NAS and SAN platforms support integration with enterprise backup software. Storage-level snapshots reduce the time required to capture backups and minimize the impact on production performance. SANs often integrate directly with virtualization and backup platforms to streamline backup scheduling and retention. This certification includes aligning backup strategies with shared storage capabilities.
Shared storage plays a central role in disaster recovery. In clustered environments, shared volumes allow failover between nodes when one system becomes unavailable. SAN-based systems may use synchronous replication across sites to support near-zero recovery time objectives. NAS devices can replicate data to another NAS unit or cloud target for geographic redundancy. A well-planned shared storage strategy ensures business continuity even during major outages or site failures.
Proper documentation of shared storage environments is essential for ongoing operations. Administrators must maintain network diagrams that include internet protocol addresses, world wide names, logical unit number assignments, and storage pool configurations. These records assist in audits, capacity upgrades, and issue resolution. Misconfiguration in shared storage can lead to data loss or access conflicts, so accurate documentation is a requirement. Server Plus emphasizes mapping and labeling shared storage topologies.
Shared storage provides the backbone for scalable and resilient infrastructure. It supports application growth, centralized control, and fast recovery from failure. Understanding the distinctions between network attached storage and storage area networks allows technicians to design, deploy, and maintain effective systems. In the next episode, we will take a deeper look at SAN technologies including iSCSI, Fibre Channel, and Fibre Channel over Ethernet, and how they are used to provide block-level storage access in high-performance environments.