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Create a MongoDB cluster that will grow to meet the needs of your application. With this short and concise book, you'll get guidelines for setting up and using clusters to store a large volume of data, and learn how to access the data efficiently. In the process, you'll understand how to make your application work with a distributed database system.
Scaling MongoDB will help you:
- Set up a MongoDB cluster through sharding
- Work with a cluster to query and update data
- Operate, monitor, and backup your cluster
- Plan your application to deal with outages
By following the advice in this book, you'll be well on your way to building and running an efficient, predictable distributed system using MongoDB.
Access to the cluster via a queue. A queue can allow your application to continue handling writes in a planned outage, or at least prevent any writes that didn’t quite make it before the outage from getting lost. You can keep them on the queue until MongoDB is up again and then send them to the mongos. A queue isn’t only useful for disasters—it can also be helpful in regulating bursty traffic. A queue can hold the burst and release a nice, constant stream of requests, instead of allowing a.
Application at all. The other servers in the set will pick up the slack and your application won’t even notice the change. Tip In 1.6, if a replica set configuration changes, there may be a zillion identical messages printed to the log. Every connection between mongos and the shard prints a message when it notices that its replica set connection is out-of-date and updates it. However, it shouldn’t have an impact on what’s actually happening—it’s just a lot of sound and fury. This has been.
Is to run one mongos on each appserver and have each appserver talk to its local mongos (Figure 5-2). Then, if the whole machine goes down, no one is trying to talk to a mongos that isn’t there. Figure 5-2. An appserver running a mongos. Have a couple extra mongos servers out there that you can fail over to if one mongos process crashes while the application server is still okay. Most drivers let you specify a list of servers to connect to and will try them in order. So, you could specify.
About trying to hack data-center awareness into MongoDB’s sharding. Sharding does not yet support data center awareness. If you’re interested in this, you can watch/vote for the relevant bug. The problem with hacking it together yourself is that it isn’t very extensible. What happens if your application is big in Japan? Now you want to add a second shard to handle Asia. How are you going to migrate data over? You can’t move a chunk once it’s more than a few gigabytes in size, and you can’t.
Command: $ python sharding/simple-setup.py --path=/path/to/your/mongodb/binaries There are a number of other options available—run python sharding/simple-setup.py --help to see them. This script is a bit finicky, so make sure to use the full path (e.g., /home/user/mongo-install, not ~/mongo-install). simple-setup.py starts up a mongos on localhost:27017, so you can connect to it with the shell to play around. If you are interested in setting up a serious-business cluster, read on. Config.