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Web service caches in Amazon EC2

You can create, store, and use ArcGIS map and image service caches on Amazon EC2 in much the same way that you do on premises. For small caches, you'll notice little difference in your caching workflow, and you can even transfer existing caches to the cloud with relative ease. For larger caches, you'll need to decide whether to transfer an on-premises cache to the cloud or create the cache from scratch on the cloud.

Caching on the cloud offers you access to powerful machines that you can use for just as long as it takes to make the cache. When you're done, you can terminate the instances and incur no further charges for these machines.

Should you move your existing cache to the cloud?

Moving files to Amazon Web Services (AWS) is not as easy as moving files from one machine to another within your network. As detailed in Strategies for data transfer to Amazon Web Services, you need to decide on a method of file transfer. You also need to appropriately secure that method of file transfer in accordance with the sensitivity of your data, then transfer the files. The speed of the transfer is limited by your Internet connection and often takes much longer than a file transfer within your own network.

The above issues are compounded with map caches since, in the exploded format, these can consist of thousands and sometimes millions of files. Sometimes, the large number of files involved in the transfer can be more of a burden than the total size. If you know that the cache will be transferred between machines, on the cloud or on premises, you should use the compact cache format whenever possible.

Before you move an exploded cache to AWS, you might want to try transferring just a small portion and extrapolate an estimate of how long it would take to move the entire cache. Similarly, you might re-create a small piece of the cache using an EC2 instance to determine whether re-creating the cache on the cloud would be a faster option. Although regenerating your entire cache may seem like an unattractive prospect, an EC2 instance can often generate tiles much faster than you can copy exploded tiles to EC2.

If you have an extraordinarily large cache that you have invested weeks or months of time to build, you might consider mailing the cache to Amazon and paying them to load the cache directly into the cloud. See AWS documentation on moving data to the cloud for more information.