What is parallel storage?

A parallel storage file system is a sort of clustered file system. A clustered file system is a storage system shared by multiple devices simultaneously.

The data is spread amongst several storage nodes for redundancy and performance in a parallel file system. In this system, the physical storage device is built using the storage devices of multiple servers. When the file system receives data, it distributes it across several storage nodes after breaking it into data blocks.

Parallel file storages duplicate the data on the physically distinct nodes. This lets the system be fault-tolerant and permits data redundancy. The data distribution improves the system’s performance and makes it faster.

In other words, the parallel file system breaks data into blocks and distributes the blocks to multiple storage servers. It uses a global namespace to enable data access. The data is written/ read using different input/ output (I/O) paths.

Examples of parallel file systems include:

• BeeGFS
• Lustre
• PanFS (Panasas)
• OrangeFS

What is distributed storage?

Distributed storage systems are also called network file systems. These systems share access to the same storage using network protocols. They prevent access to the file system based on the access lists and capabilities of the server and client systems. They allow access to files using the same interfaces as local files. 

A parallel file system is a kind of distributed file system. Both systems share data amongst multiple servers.

Examples of distributed file systems available in the market include:

• Windows DFS
• Infinit
• Alluxio
• ObjectiveFS
• JuiceFS
• MapR FS

Features of distributed file systems

• The clients should access the distributed files as they would access local files, and they should not be aware of the file distribution.
• The client system and program should function correctly even when a server failure occurs.
• The file should be compatible across various hardware and operating systems.
• All the clients should get the same view of the file in the system. For instance, if a file is being modified, all the clients accessing the file should see the changes.
• The clients should not be informed about the data duplication.
• The systems should be scalable. This means that if a system works in a small environment, it should work for a larger environment.

Difference between parallel and distributed file system

Advantages of parallel file systems

The advantages of using parallel file systems for data storage are as mentioned below:

• They improve the system’s performance.
• They give fast access to the data, especially when large amounts of stored data have to be accessed.
• They are highly scalable.
• They allow multiple clients/ users to use the data at the same time.
• They support data redundancy.
• They are stable.

Disadvantages of parallel file systems

The disadvantages of using parallel file systems are as follows:

• Parallel file systems are expensive than other storage systems.
• Trained people are required to handle parallel file systems.
• The cost of maintaining parallel systems is high.

Uses of parallel file systems

Parallel file systems are mainly used in high-performance computing (HPC) applications that handle large data and files. Some of these applications include:

• Climate modeling
• Genomic sequencing
• Seismic processing
• Video editing

Advantages of distributed file systems

The benefits of using distributed file systems for data storage is as follows:

• They allow multiple users to access and store data.
• They allow remote data sharing.
• They are easier to implement.
• They increase the ability to change the amount of data and exchange data.
• The data uptime is higher. 

Disadvantages of distributed file systems

The downsides of using distributed file systems for data storage are as follows:

• The database connection in distributed file systems is complex.
• Since more than one user may access the same data simultaneously, data handling becomes tough.
• The system requires high security since all nodes and connections to be secured.
• If simultaneous data transfer fails, overloading might occur.
• The data may get lost while transferring data from one node to another in the system.
• The read/ write speed of the system will get slower while handling large amounts of data.

Uses of distributed file systems

Distributed file systems are used in various software applications, such as:

• Hadoop - It gives a framework for handling large amounts of data and distributing storage.
• Network File System - A client-server architecture used for accessing, storing, and modifying data files remotely.
• Server Message Block - A protocol used for file sharing.
• Netware - An abandoned computer network operating system.

Context and Applications

The topic parallel and distributed storage is a significant database concept covered in graduate and postgraduate courses like:

• Bachelor of Technology in Computer Science Engineering
• Master of Technology in Computer Science Engineering
• Master of Science in Data Science and Analytics
• Master of Science in Computer Networking

Practice Problems

1. Which of these is an application of distributed file system?

1. Network File System
2. Kubernetes
3. State-of-the-art
4. Storage area network

Answer: Option a

Explanation: The Network File System is an application of distributed file system.

2. Which file system breaks the file into data blocks before distribution?

1. Parallel processing
2. Parallel file system
3. Cloud storage
4. Multiple systems

Answer: Option b

Explanation: The parallel file system divides the file into data blocks and distributes the blocks to the servers.

3. The distributed file system stores data amongst how many nodes?

1. Small files computing
2. One
3. Data-intensive cluster computing
4. High availability cluster

Answer: Option b

Explanation: The distributed file system stores data across only one node.

4. Which of these is an advantage of the distributed file system?

1. Panasas cluster user
2. It has a high uptime
3. Kubernetes
4. Parallel processing

Answer: Option b

Explanation: One of the advantages of the distributed file system is that it has a high uptime.

5. Which of these is a disadvantage of the parallel file system?

1. PanFS high availability
2. BeeGFS
3. It is expensive
4. Data-intensive 

Answer: Option c

Explanation: The main disadvantage of using the parallel file system for data storage is that it is expensive than other systems.

Common Mistakes

Students often get confused between parallel and distributed file systems. However, they should understand the basic difference between these systems and not mix up their meanings and applications.

Related concepts

• Distributed file system for cloud
• Hadoop distributed file system 
• Cloud computing
• Cluster-based architectures