1.2 Given a scenario, deploy and manage storage.
📘CompTIA Server+ (SK0-005)
Shared storage is storage that multiple computers (servers or clients) can access over a network. It’s essential in IT environments because it allows:
- Multiple servers to access the same data simultaneously.
- Centralized data management.
- Better data backup, redundancy, and collaboration.
There are two main types of shared storage:
- Network Attached Storage (NAS)
- Storage Area Network (SAN)
We will go through each in detail.
1. Network Attached Storage (NAS)
NAS is a storage device connected to a network that provides file-level access to data. Think of it as a “file server” that any authorized device on the network can reach.
- File-level access: Users access files and folders directly over the network.
- NAS is easier to set up and manage than SAN.
- NAS is ideal for file sharing, backups, and collaboration.
NAS uses specific protocols to share files:
a) Network File System (NFS)
- NFS is mainly used in Linux/Unix environments.
- It allows servers and clients to read and write files over the network as if they were on a local disk.
- NFS mounts remote directories locally, so users can work with them like any folder on their machine.
Key points for exams:
- Works well in mixed Linux/Unix networks.
- Operates over TCP/IP networks.
- Uses port 2049 by default.
Example: A Linux server can mount an NFS share from a NAS to store backup logs.
b) Common Internet File System (CIFS)
- CIFS is primarily used in Windows environments.
- It’s an extension of the Server Message Block (SMB) protocol.
- Allows Windows computers to access shared folders and files on NAS devices over a network.
Key points for exams:
- Works best in Windows networks.
- Operates over TCP/IP, usually port 445.
- Supports file permissions and user authentication.
Example: A Windows server connects to a NAS share using CIFS to access shared project files.
Summary of NAS protocols:
| Protocol | Typical OS | Port | Use Case |
|---|---|---|---|
| NFS | Linux/Unix | 2049 | Linux file sharing |
| CIFS/SMB | Windows | 445 | Windows file sharing |
Remember: NAS = file-level storage, easy to set up, ideal for shared documents, backups, or small-scale collaboration.
2. Storage Area Network (SAN)
SAN is a high-speed network of storage devices that provides block-level access. Unlike NAS, SAN acts like a local hard drive to the server.
- Block-level storage: The server reads and writes raw blocks of data, not files.
- SAN is faster and more suitable for databases, virtual machines, and enterprise applications.
- Requires special protocols and network hardware.
SAN Protocols:
a) Internet Small Computer Systems Interface (iSCSI)
- iSCSI allows block-level storage over regular TCP/IP networks.
- Uses Ethernet networks, so no need for specialized Fibre Channel hardware.
- Servers see iSCSI storage as a local disk.
Key points for exams:
- Uses TCP port 3260.
- Can work over long distances.
- Often used in medium-sized businesses because it’s cheaper than Fibre Channel.
Example: A virtual machine server connects to a SAN via iSCSI to store virtual disks.
b) Fibre Channel (FC)
- Fibre Channel is a high-speed network protocol designed for SANs.
- Provides very fast, low-latency access to block-level storage.
- Requires special FC switches and HBAs (Host Bus Adapters) in servers.
Key points for exams:
- Speeds up to 32 Gbps or more.
- Works as a dedicated storage network (separate from regular Ethernet).
- Ideal for large enterprise environments with heavy data workloads.
Example: A database server in a data center uses Fibre Channel SAN for fast access to transactional data.
c) Fibre Channel over Ethernet (FCoE)
- FCoE combines Fibre Channel traffic over standard Ethernet networks.
- Eliminates the need for separate Fibre Channel cables.
- Maintains high performance while reducing infrastructure costs.
Key points for exams:
- Requires lossless Ethernet (Converged Network Adapter – CNA).
- Ideal for organizations that want high performance SAN without separate Fibre Channel networks.
Example: A data center runs FCoE to consolidate both server network traffic and storage traffic on the same high-speed Ethernet network.
Key Differences Between NAS and SAN
| Feature | NAS | SAN |
|---|---|---|
| Storage Level | File-level | Block-level |
| Access Protocols | NFS, CIFS/SMB | iSCSI, FC, FCoE |
| Network Type | Standard TCP/IP network | High-speed network (Ethernet or Fibre Channel) |
| Performance | Moderate | High |
| Use Case | File sharing, backups | Databases, virtualization |
Exam Tips:
- Know the difference: NAS = file-level, SAN = block-level.
- Associate protocols with OS and type:
- NFS → Linux, file-level
- CIFS/SMB → Windows, file-level
- iSCSI → Block-level, TCP/IP
- Fibre Channel → Block-level, high speed
- FCoE → Block-level, Ethernet + Fibre Channel
- Ports and transport: Some questions may ask about default ports (NFS 2049, CIFS 445, iSCSI 3260).
- Use cases: NAS for general file sharing; SAN for enterprise apps needing speed and reliability.
