AWS Storage Gateway User Guide
Sizing Cache Storage
any of your volume data to its upload buffer and does not upload any of this data to AWS until
Storage Gateway synchronizes the data stored locally with the copy of the data stored in AWS.
This synchronization occurs when the volumes are in BOOTSTRAPPING status.
To estimate the amount of upload buffer to allocate, you can determine the expected incoming and
outgoing data rates and plug them into the following formula.
Rate of incoming data
This rate refers to the application throughput, the rate at which your on-premises applications write
data to your gateway over some period of time.
Rate of outgoing data
This rate refers to the network throughput, the rate at which your gateway is able to upload data to
AWS. This rate depends on your network speed, utilization, and whether you've enabled bandwidth
throttling. This rate should be adjusted for compression. When uploading data to AWS, the gateway
applies data compression where possible. For example, if your application data is text-only, you
might get an effective compression ratio of about 2:1. However, if you are writing videos, the
gateway might not be able to achieve any data compression and might require more upload buffer
for the gateway.
We strongly recommend that you allocate at least 150 GiB of upload buffer space if either of the
following is true: Your incoming rate is higher than the outgoing rate, The formula returns a value less
than 150 GiB.
For example, assume that your business applications write text data to your gateway at a rate of 40
MB per second for 12 hours per day and your network throughput is 12 MB per second. Assuming a
compression factor of 2:1 for the text data, you would allocate approximately 690 GiB of space for the
upload buffer.
Example
((40 MB/sec) - (12 MB/sec * 2)) * (12 hours * 3600 seconds/hour) = 691200 megabytes
You can initially use this approximation to determine the disk size that you want to allocate to the
gateway as upload buffer space. Add more upload buffer space as needed using the Storage Gateway
console. Also, you can use the Amazon CloudWatch operational metrics to monitor upload buffer usage
and determine additional storage requirements. For information on metrics and setting the alarms, see
Monitoring the Upload Buffer (p. 196)
.
Determining the Size of Cache Storage to Allocate
Your gateway uses its cache storage to provide low-latency access to your recently accessed data. The
cache storage acts as the on-premises durable store for data that is pending upload to Amazon S3 from
the upload buffer. Generally speaking, you size the cache storage at 1.1 times the upload buffer size. For
more information about how to estimate your cache storage size, see
Determining the Size of Upload
You can initially use this approximation to provision disks for the cache storage. You can then use
Amazon CloudWatch operational metrics to monitor the cache storage usage and provision more storage
as needed using the console. For information on using the metrics and setting up alarms, see
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