Welcome!

Linux Containers Authors: Elizabeth White, Pat Romanski, Liz McMillan, Richard Hale, XebiaLabs Blog

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
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develo...
The IETF draft standard for M2M certificates is a security solution specifically designed for the demanding needs of IoT/M2M applications. In his session at @ThingsExpo, Brian Romansky, VP of Strategic Technology at TrustPoint Innovation, explained how M2M certificates can efficiently enable confidentiality, integrity, and authenticity on highly constrained devices.
SYS-CON Events announced today that MangoApps will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. MangoApps provides modern company intranets and team collaboration software, allowing workers to stay connected and productive from anywhere in the world and from any device.
"We've discovered that after shows 80% if leads that people get, 80% of the conversations end up on the show floor, meaning people forget about it, people forget who they talk to, people forget that there are actual business opportunities to be had here so we try to help out and keep the conversations going," explained Jeff Mesnik, Founder and President of ContentMX, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Internet of @ThingsExpo has announced today that Chris Matthieu has been named tech chair of Internet of @ThingsExpo 2016 Silicon Valley. The 6thInternet of @ThingsExpo will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
When people aren’t talking about VMs and containers, they’re talking about serverless architecture. Serverless is about no maintenance. It means you are not worried about low-level infrastructural and operational details. An event-driven serverless platform is a great use case for IoT. In his session at @ThingsExpo, Animesh Singh, an STSM and Lead for IBM Cloud Platform and Infrastructure, will detail how to build a distributed serverless, polyglot, microservices framework using open source tec...
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, 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 opportuni...
From wearable activity trackers to fantasy e-sports, data and technology are transforming the way athletes train for the game and fans engage with their teams. In his session at @ThingsExpo, will present key data findings from leading sports organizations San Francisco 49ers, Orlando Magic NBA team. By utilizing data analytics these sports orgs have recognized new revenue streams, doubled its fan base and streamlined costs at its stadiums. John Paul is the CEO and Founder of VenueNext. Prior ...
A critical component of any IoT project is what to do with all the data being generated. This data needs to be captured, processed, structured, and stored in a way to facilitate different kinds of queries. Traditional data warehouse and analytical systems are mature technologies that can be used to handle certain kinds of queries, but they are not always well suited to many problems, particularly when there is a need for real-time insights.
CenturyLink has announced that application server solutions from GENBAND are now available as part of CenturyLink’s Networx contracts. The General Services Administration (GSA)’s Networx program includes the largest telecommunications contract vehicles ever awarded by the federal government. CenturyLink recently secured an extension through spring 2020 of its offerings available to federal government agencies via GSA’s Networx Universal and Enterprise contracts. GENBAND’s EXPERiUS™ Application...
"My role is working with customers, helping them go through this digital transformation. I spend a lot of time talking to banks, big industries, manufacturers working through how they are integrating and transforming their IT platforms and moving them forward," explained William Morrish, General Manager Product Sales at Interoute, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 19th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo Silicon Valley Call for Papers is now open.
Big Data engines are powering a lot of service businesses right now. Data is collected from users from wearable technologies, web behaviors, purchase behavior as well as several arbitrary data points we’d never think of. The demand for faster and bigger engines to crunch and serve up the data to services is growing exponentially. You see a LOT of correlation between “Cloud” and “Big Data” but on Big Data and “Hybrid,” where hybrid hosting is the sanest approach to the Big Data Infrastructure pro...
The IoT is changing the way enterprises conduct business. In his session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, discussed how businesses can gain an edge over competitors by empowering consumers to take control through IoT. He cited examples such as a Washington, D.C.-based sports club that leveraged IoT and the cloud to develop a comprehensive booking system. He also highlighted how IoT can revitalize and restore outdated business models, making them profitable ...
We all know the latest numbers: Gartner, Inc. forecasts that 6.4 billion connected things will be in use worldwide in 2016, up 30 percent from last year, and will reach 20.8 billion by 2020. We're rapidly approaching a data production of 40 zettabytes a day – more than we can every physically store, and exabytes and yottabytes are just around the corner. For many that’s a good sign, as data has been proven to equal money – IF it’s ingested, integrated, and analyzed fast enough. Without real-ti...
I wanted to gather all of my Internet of Things (IOT) blogs into a single blog (that I could later use with my University of San Francisco (USF) Big Data “MBA” course). However as I started to pull these blogs together, I realized that my IOT discussion lacked a vision; it lacked an end point towards which an organization could drive their IOT envisioning, proof of value, app dev, data engineering and data science efforts. And I think that the IOT end point is really quite simple…
With 15% of enterprises adopting a hybrid IT strategy, you need to set a plan to integrate hybrid cloud throughout your infrastructure. In his session at 18th Cloud Expo, Steven Dreher, Director of Solutions Architecture at Green House Data, discussed how to plan for shifting resource requirements, overcome challenges, and implement hybrid IT alongside your existing data center assets. Highlights included anticipating workload, cost and resource calculations, integrating services on both sides...
"We are a well-established player in the application life cycle management market and we also have a very strong version control product," stated Flint Brenton, CEO of CollabNet,, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
The IoT has the potential to create a renaissance of manufacturing in the US and elsewhere. In his session at 18th Cloud Expo, Florent Solt, CTO and chief architect of Netvibes, discussed how the expected exponential increase in the amount of data that will be processed, transported, stored, and accessed means there will be a huge demand for smart technologies to deliver it. Florent Solt is the CTO and chief architect of Netvibes. Prior to joining Netvibes in 2007, he co-founded Rift Technologi...
We're entering the post-smartphone era, where wearable gadgets from watches and fitness bands to glasses and health aids will power the next technological revolution. With mass adoption of wearable devices comes a new data ecosystem that must be protected. Wearables open new pathways that facilitate the tracking, sharing and storing of consumers’ personal health, location and daily activity data. Consumers have some idea of the data these devices capture, but most don’t realize how revealing and...