Welcome!

Open Source Cloud Authors: Scott Millis, Elizabeth White, XebiaLabs Blog, Pat Romanski, Liz McMillan

Related Topics: Containers Expo Blog, Java IoT, Linux Containers, Open Source Cloud

Containers Expo Blog: Blog Post

GridFS and MongoDB: Pros and Cons

Should I use GridFS for file storage with MongoDB

GridFS looks like a great idea on paper - a virtual filesystem held within MongoDB which allows for larger than 16MB files to be held, synced and replicated. It's very tempting when architecting your solutions to want to consider using GridFS. It appears to be able to take on the problem of storing many thousands or millions of files without consuming file-system resources where there are often hard limits on the number of file names. It also seems to allow for massive files to be stored without any obvious downsides.

It is important, though, to know what GridFS is under the hood. For any file being stored with GridFS, the file is chopped into 255KB chunks. Those chunks are saved in a bucket, called fs, and a collection in that bucket, fs.chunks. Metadata about the files is stored in another collection in the same bucket, fs.files, though you can have more buckets with different bucket names in the same database. An index makes retrieving the chunks quick. All this chunking and metadata management is not done by the MongoDB database though. It is a task performed by the client's driver which is then wrapped in a GridFS API for that driver.

When you put or retrieve a large file of size nKB, in its entirety, what is happening is the driver is retrieving all the relevant chunks, all nKB/255KB chunks, as documents, assembling them at the client end and writing them out to wherever they are needed. So a 16MB file is retrieved as 65 documents of 255K each. Consider what would happen if you did that regularly on your MongoDB database outside of GridFS; there would be severe competition for the servers RAM between those documents and the rest of the database.

The chunking with GridFS and the fact that it is done by the driver also means that large operations like replacing an entire file within GridFS are not atomic and there's no built in versioning to fall back on. This may, or may not, be a problem for some applications where files are concurrently accessible by many users or their applications. You can, though, work around this by layering on your own versioning scheme over GridFS, only making replacement files the latest version when they have completed writing.

There is an upside of to chunking though - it is remarkably cheap to access particular sections of files because they are broken up into manageable blocks during the chunking so if you need to access particular parts of large binary files, you won't be pushing the working set out of memory in the server. You can also adjust the chunk size so if your application would work better with a smaller or larger chunk, you can tune your GridFS usage by requesting a particular size of chunk. Smaller chunks would push fewer parts of the working set out of memory, larger chunks less so.

You can avoid the entire issue of contention with your working set of data by having another MongoDB server dedicated to GridFS storage and optimized towards your file storage use patterns. This also lets you focus on tuning the best performance out of your core database instance without having to look over your shoulder for the march of the GridFS files through your working set. With MongoHQ, creating a separate database instance is easier than ever and there'll be a plan to suit your needs.

If you are dealing with files less than 16MB and want to handle them as atomic entities, it is also worth considering whether you need to use GridFS at all because you can have MongoDB documents with 16MB fields. You will have to ensure that when reading the database, you only pull the large fields into memory when you need to, but this does give you the atomic replacement writes and architecturally simpler system you may desire. The down side is that access to binary ranges within the file will likely require downloading the file, modifying it and re-writing it, but it is all about balance and matching your file storage and use patterns.

So, as we said at the beginning, "it depends" if GridFS is a good fit for your application's file storage needs. There are some pitfalls which you can avoid at planning time with some estimates of what quantity of file data you want to store and how you want to access it. There are also many benefits to a MongoDB and GridFS solution, especially in terms of replication and synchronization.

More Stories By DJ Walker-Morgan

Content Curator at MongoHQ, Dj has been both a developer and writer since Apples came in ][ flavors and Commodores had Pets.

@ThingsExpo Stories
According to Forrester Research, every business will become either a digital predator or digital prey by 2020. To avoid demise, organizations must rapidly create new sources of value in their end-to-end customer experiences. True digital predators also must break down information and process silos and extend digital transformation initiatives to empower employees with the digital resources needed to win, serve, and retain customers.
The WebRTC Summit New York, to be held June 6-8, 2017, at the Javits Center in New York City, NY, announces that its Call for Papers is now open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 20th International Cloud Expo and @ThingsExpo. WebRTC is the future of browser-to-browser communications, and continues to make inroads into the traditional, difficult, plug-in web co...
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
The Internet of Things (IoT) promises to simplify and streamline our lives by automating routine tasks that distract us from our goals. This promise is based on the ubiquitous deployment of smart, connected devices that link everything from industrial control systems to automobiles to refrigerators. Unfortunately, comparatively few of the devices currently deployed have been developed with an eye toward security, and as the DDoS attacks of late October 2016 have demonstrated, this oversight can ...
"We're a cybersecurity firm that specializes in engineering security solutions both at the software and hardware level. Security cannot be an after-the-fact afterthought, which is what it's become," stated Richard Blech, Chief Executive Officer at Secure Channels, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
What happens when the different parts of a vehicle become smarter than the vehicle itself? As we move toward the era of smart everything, hundreds of entities in a vehicle that communicate with each other, the vehicle and external systems create a need for identity orchestration so that all entities work as a conglomerate. Much like an orchestra without a conductor, without the ability to secure, control, and connect the link between a vehicle’s head unit, devices, and systems and to manage the ...
"Once customers get a year into their IoT deployments, they start to realize that they may have been shortsighted in the ways they built out their deployment and the key thing I see a lot of people looking at is - how can I take equipment data, pull it back in an IoT solution and show it in a dashboard," stated Dave McCarthy, Director of Products at Bsquare Corporation, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, discussed the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
Businesses and business units of all sizes can benefit from cloud computing, but many don't want the cost, performance and security concerns of public cloud nor the complexity of building their own private clouds. Today, some cloud vendors are using artificial intelligence (AI) to simplify cloud deployment and management. In his session at 20th Cloud Expo, Ajay Gulati, Co-founder and CEO of ZeroStack, will discuss how AI can simplify cloud operations. He will cover the following topics: why clou...
As data explodes in quantity, importance and from new sources, the need for managing and protecting data residing across physical, virtual, and cloud environments grow with it. Managing data includes protecting it, indexing and classifying it for true, long-term management, compliance and E-Discovery. Commvault can ensure this with a single pane of glass solution – whether in a private cloud, a Service Provider delivered public cloud or a hybrid cloud environment – across the heterogeneous enter...
Everyone knows that truly innovative companies learn as they go along, pushing boundaries in response to market changes and demands. What's more of a mystery is how to balance innovation on a fresh platform built from scratch with the legacy tech stack, product suite and customers that continue to serve as the business' foundation. In his General Session at 19th Cloud Expo, Michael Chambliss, Head of Engineering at ReadyTalk, discussed why and how ReadyTalk diverted from healthy revenue and mor...
The many IoT deployments around the world are busy integrating smart devices and sensors into their enterprise IT infrastructures. Yet all of this technology – and there are an amazing number of choices – is of no use without the software to gather, communicate, and analyze the new data flows. Without software, there is no IT. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, Dave McCarthy, Director of Products at Bsquare Corporation; Alan Williamson, Principal...
The 20th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held June 6-8, 2017, at the Javits Center in New York City, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Containers, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal ...
You have great SaaS business app ideas. You want to turn your idea quickly into a functional and engaging proof of concept. You need to be able to modify it to meet customers' needs, and you need to deliver a complete and secure SaaS application. How could you achieve all the above and yet avoid unforeseen IT requirements that add unnecessary cost and complexity? You also want your app to be responsive in any device at any time. In his session at 19th Cloud Expo, Mark Allen, General Manager of...
Successful digital transformation requires new organizational competencies and capabilities. Research tells us that the biggest impediment to successful transformation is human; consequently, the biggest enabler is a properly skilled and empowered workforce. In the digital age, new individual and collective competencies are required. In his session at 19th Cloud Expo, Bob Newhouse, CEO and founder of Agilitiv, drew together recent research and lessons learned from emerging and established compa...
"IoT is going to be a huge industry with a lot of value for end users, for industries, for consumers, for manufacturers. How can we use cloud to effectively manage IoT applications," stated Ian Khan, Innovation & Marketing Manager at Solgeniakhela, in this SYS-CON.tv interview at @ThingsExpo, held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA.
Information technology is an industry that has always experienced change, and the dramatic change sweeping across the industry today could not be truthfully described as the first time we've seen such widespread change impacting customer investments. However, the rate of the change, and the potential outcomes from today's digital transformation has the distinct potential to separate the industry into two camps: Organizations that see the change coming, embrace it, and successful leverage it; and...
Bert Loomis was a visionary. This general session will highlight how Bert Loomis and people like him inspire us to build great things with small inventions. In their general session at 19th Cloud Expo, Harold Hannon, Architect at IBM Bluemix, and Michael O'Neill, Strategic Business Development at Nvidia, discussed the accelerating pace of AI development and how IBM Cloud and NVIDIA are partnering to bring AI capabilities to "every day," on-demand. They also reviewed two "free infrastructure" pr...
Financial Technology has become a topic of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 20th Cloud Expo at the Javits Center in New York, June 6-8, 2017, will find fresh new content in a new track called FinTech.
"Dice has been around for the last 20 years. We have been helping tech professionals find new jobs and career opportunities," explained Manish Dixit, VP of Product and Engineering at Dice, in this SYS-CON.tv interview at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.