Welcome!

Java Authors: Pat Romanski, Liz McMillan, Elizabeth White, Jason Bloomberg, Trevor Parsons

Related Topics: Virtualization, Java, Linux, Open Source

Virtualization: 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
How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff happens, where data lives and where the interface lies. For instance, it's a mix of architectural styles ...
We are reaching the end of the beginning with WebRTC, and real systems using this technology have begun to appear. One challenge that faces every WebRTC deployment (in some form or another) is identity management. For example, if you have an existing service – possibly built on a variety of different PaaS/SaaS offerings – and you want to add real-time communications you are faced with a challenge relating to user management, authentication, authorization, and validation. Service providers will want to use their existing identities, but these will have credentials already that are (hopefully) i...
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, discussed how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money!
The Internet of Things will put IT to its ultimate test by creating infinite new opportunities to digitize products and services, generate and analyze new data to improve customer satisfaction, and discover new ways to gain a competitive advantage across nearly every industry. In order to help corporate business units to capitalize on the rapidly evolving IoT opportunities, IT must stand up to a new set of challenges. In his session at @ThingsExpo, Jeff Kaplan, Managing Director of THINKstrategies, will examine why IT must finally fulfill its role in support of its SBUs or face a new round of...
Cultural, regulatory, environmental, political and economic (CREPE) conditions over the past decade are creating cross-industry solution spaces that require processes and technologies from both the Internet of Things (IoT), and Data Management and Analytics (DMA). These solution spaces are evolving into Sensor Analytics Ecosystems (SAE) that represent significant new opportunities for organizations of all types. Public Utilities throughout the world, providing electricity, natural gas and water, are pursuing SmartGrid initiatives that represent one of the more mature examples of SAE. We have s...
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, described an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-device experiences grounded in people's real needs and desires.
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, examined three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective storage designed to handle the massive surge in back-end data in a world where timely analytics is e...
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at @ThingsExpo, Robin Raymond, Chief Architect at Hookflash, will walk through the shifting landscape of traditional telephone and voice services ...
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using the URL as a basic building block, we open this up and get the same resilience that the web enjoys.
The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, discussed single-value, geo-spatial, and log time series data. By focusing on enterprise applications and the data center, he will use OpenTSDB as an example t...
The Domain Name Service (DNS) is one of the most important components in networking infrastructure, enabling users and services to access applications by translating URLs (names) into IP addresses (numbers). Because every icon and URL and all embedded content on a website requires a DNS lookup loading complex sites necessitates hundreds of DNS queries. In addition, as more internet-enabled ‘Things' get connected, people will rely on DNS to name and find their fridges, toasters and toilets. According to a recent IDG Research Services Survey this rate of traffic will only grow. What's driving t...
Enthusiasm for the Internet of Things has reached an all-time high. In 2013 alone, venture capitalists spent more than $1 billion dollars investing in the IoT space. With "smart" appliances and devices, IoT covers wearable smart devices, cloud services to hardware companies. Nest, a Google company, detects temperatures inside homes and automatically adjusts it by tracking its user's habit. These technologies are quickly developing and with it come challenges such as bridging infrastructure gaps, abiding by privacy concerns and making the concept a reality. These challenges can't be addressed w...
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Architect for the Internet of Things and Intelligent Systems at Red Hat, described how to revolutioniz...
Bit6 today issued a challenge to the technology community implementing Web Real Time Communication (WebRTC). To leap beyond WebRTC’s significant limitations and fully leverage its underlying value to accelerate innovation, application developers need to consider the entire communications ecosystem.
The definition of IoT is not new, in fact it’s been around for over a decade. What has changed is the public's awareness that the technology we use on a daily basis has caught up on the vision of an always on, always connected world. If you look into the details of what comprises the IoT, you’ll see that it includes everything from cloud computing, Big Data analytics, “Things,” Web communication, applications, network, storage, etc. It is essentially including everything connected online from hardware to software, or as we like to say, it’s an Internet of many different things. The difference ...
Cloud Expo 2014 TV commercials will feature @ThingsExpo, which was launched in June, 2014 at New York City's Javits Center as the largest 'Internet of Things' event in the world.
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, phone and digital TV services to consumers primarily in rural areas.
"There is a natural synchronization between the business models, the IoT is there to support ,” explained Brendan O'Brien, Co-founder and Chief Architect of Aria Systems, in this SYS-CON.tv interview at the 15th International Cloud Expo®, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com), moderated by Ashar Baig, Research Director, Cloud, at Gigaom Research, Nate Gordon, Director of T...