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Cloud Block Store - AWS Data Transfer Costs

 

Introduction

This document explains the AWS costs incurred when transferring data to and from Cloud Block Store (CBS) instances in AWS. Following are the types of scenarios in which CBS data transfers take place: 

  • Replication of data across CBS instances
  • Replication of data between a CBS instance and an on-prem FlashArray
  • Data backup/restore between a CBS instance and an Amazon S3 bucket via CloudSnap

This document lists the different data transfer scenarios, along with the associated AWS costs. The prices listed in this document are examples based on AWS prices at the time of writing. Users should always check the AWS website for the latest pricing for their specific AWS region. 

 

 

The amount of data transferred by CBS

In order to understand CBS data transfer costs, we need to first understand the amount of data that is transferred during the different types of CBS data transfers, which can be divided in the following 2 types:

  1. Replication across CBS instances, or between CBS instances and on-prem FlashArrays
  2. CBS backups and restores to an AWS S3 bucket using CloudSnap

 

The amount of data transferred during CBS replication

CBS replication includes replication across CBS instances, and between CBS instances and on-prem FlashArrays.

Like the FlashArray, CBS also stores data in a highly compressed and deduplicated form for maximum space efficiency and miminum storage costs. Asyc replication preserves this compression and deduplication when transferring data, which helps reduce data transfer times, as well as AWS data transfer costs. 

In addition to the above, when a volume is replicated from one CBS instance (or FlashArray) to another, only the first copy is full, and all subsequent copies are deltas only. This is explained in more detail below:

When replication of a volume is initially set up on CBS (or a FlashArray), since the volume is not already present on the destination array, the entire contents of the volume are transferred from the source array to the destination array in a compressed and deduplicated form. This is stored on the destination in its entirety, and it establishes a baseline on the destination array.

Once a baseline has been established, during subsequent replications of the same volume, only the delta changes in data since the time of the previous snapshot are sent to the destination array. In order to prevent back and forth network traffic and AWS transfer costs, a local copy of the latest snapshot is saved on the source array, and is used to calculate the delta for the next snapshot. When the delta is received on the destination array, data that is already present from previous replications is automatically combined with the delta to form a complete snapshot.

This highly efficient replication process has the following benefits:

  • The storage footprint is reduced, lowering AWS costs
  • Data transfer costs and network utilization are minimized
  • Replication times are shorter

 

The amount of data transferred during CloudSnap backups & restores

CloudSnap preserves the data compression used in CBS for storage efficiency. However, it does not preserve the deduplication used by CBS.

During CBS backups to Amazon Simple Storage Service (S3), after the initial baseline snapshot of a volume is transferred to an S3 bucket, CloudSnap sends only the delta changes for subsequent snapshots of the same volume. A local copy of the latest snapshot is always kept on CBS to compute the delta changes. This prevents back and forth network traffic for calculating deltas between snapshots.

During restores from Amazon S3, CloudSnap pulls back only the missing data blocks from the S3 bucket. This is combined with the data blocks that are already present on the CBS instance in order to rebuild the complete snapshot. This further reduces network traffic, as well as restore times.

In summary, the amount of data transferred by CloudSnap is equal to the size of the customer’s data in a compressed (but not deduped) format. After the initial snapshot of a volume has been backed up to the S3 bucket, only the delta changes are transferred for subsequent snapshots of the same volume.

CloudSnap backups are highly efficient, and provide the following benefits:

  • The storage footprint in the S3 bucket is reduced
  • Network utilization is minimized
  • Backup & restore windows are shorter
  • Data retrieval costs from the S3 bucket are minimized

 

ActiveCluster considerations

The AWS costs incurred when replicating data from an ActiveCluster configuration are the same as the AWS costs incurred when replicating data from a single (non-ActiveCluster) array; therefore, separate cost calculations are not needed for ActiveCluster configurations.

 

 

Data transfer scenarios

Following are the different CBS replication scenarios, along with the AWS data transfer costs associated with each of them.

 

Replication from an on-prem FlashArray to a CBS instance

AWS data transfer costs are mostly unidirectional, i.e. data that is going out of AWS to the internet is subject to data transfer charges, but there’s no charge for transferring data into AWS.

Therefore, currently there are no charges associated with replicating data from an on-prem FlashArray to a CBS instance in AWS, as listed in the table below:

 

Data transfer in to Amazon EC2 from the Internet

All data transfer in

$0.00 per GB

 

Replication from a CBS instance to an on-prem FlashArray

Replication of data from a CBS instance to a FlashArray on-prem involves the egress costs associated with the transfer of data out of AWS.

The cost of replicating data from a CBS instance in AWS to a physical on-prem FlashArray is dependent on the AWS region where the CBS instance is located. For example, the current cost of replicating data out of the US-East-2 (Ohio) region is shown in Table 1 below:

 

Data transfer out from AWS US-East-2 (Ohio)

Up to 1 GB / Month

$0.00 per GB

Next 9.999 TB / Month

$0.09 per GB

Next 40 TB / Month

$0.085 per GB

Next 100 TB / Month

$0.07 per GB

Greater than 150 TB / Month

$0.05 per GB

Table 1: Cost of data replication out of the US-East-2 (Ohio) region

 

Please note that these costs vary based on the AWS region. The link below has the complete list of the current prices for transferring data out of the different AWS regions: 

https://aws.amazon.com/ec2/pricing/on-demand/

Example calculation

Let’s assume we have a volume called Volume_A located on a CBS instance in the US-East-2 (Ohio) region with the following properties:

  • Data size = 100GB
  • Compression = 2:1
  • Deduplication = 2:1
  • Daily change rate = 5%

After data reduction (compression & deduplication), the amount of data stored on the CBS instance for Volume_A is 25GB. 

If we start replicating this volume to an on-prem FlashArray at a “once per day” frequency, the initial baseline snapshot will transfer 25GB of data, and each subsequent snapshot will transfer 1.25GB of data (25GB X 5% = 1.25GB).

According to Table 1, the cost of the initial replication will be $0.09/GB X 25GB = $2.25; after that, the daily cost of replicating a subsequent snapshot will be $0.09/GB X 1.25GB = $0.1125 (assuming that the total amount of egress is in the 1GB/month to 10TB/month range).

 

Replication between CBS instances within the same AWS region and availability zone

Currently, the AWS cost for replicating data between CBS instances in the same AWS region and within the same availability zone are zero.

 

Replication between CBS instances within the same AWS region, across different availability zones

The AWS cost for replicating data between CBS instances across different availability zones in the same AWS region is considered a regional data transfer. Currently, data transfers out from the source CBS instance are charged at $0.01/GB, and data transfers into the destination CBS instance from a different availability zone within the same AWS region are also charged at $0.01/GB. This results in a total data transfer cost of $0.02/GB across availibility zones in the same AWS region.

Example calculation

Let’s take the example of Volume_A again, located on a CBS instance in the US-East-2 (Ohio) region with the following properties:

  • Data size = 100GB
  • Compression = 2:1
  • Deduplication = 2:1
  • Daily change rate = 5%

After data reduction (compression & deduplication), the amount of data stored on the CBS instance for Volume_A is 25GB. 

If we start replicating this volume to another CBS instance located in a different availability zone in the same US-East-2 (Ohio) region at a “once per day” frequency, the initial baseline snapshot will transfer 25GB of data, and each subsequent snapshot will transfer 1.25GB of data (25GB X 5% = 1.25GB).

The cost of the initial replication will be $0.02/GB X 25GB = $0.5; after that, the daily cost of replicating a subsequent snapshot will be $0.02/GB X 1.25GB = $0.025 (assuming that the total amount of egress is in the 1GB/month to 10TB/month range).

 

Replication between CBS instances across AWS regions

Transferring data into the destination AWS region from another AWS region is free, but there is a charge for outbound data transfer from the source AWS region.

The cost of replicating data across CBS instances in different AWS regions varies depending on the regions in which the source and destination CBS instances are located. Following are a couple of examples, based on current prices:

  • The cost of replicating data out of the US-East-2 (Ohio) region to the US-East-1 (N. Virginia) region is $0.01/GB
  • The cost of replicating data out of the US-East-2 (Ohio) region to any AWS region other than the US-East-1 (N. Virginia) region is $0.02/GB

The link below has a complete list of the latest prices for data transfers between different AWS regions: 

https://aws.amazon.com/ec2/pricing/on-demand/

Example calculation:

Let’s take the example of Volume_A again, located on a CBS instance in the US-East-2 (Ohio) region with the following properties:

  • Data size = 100GB
  • Compression = 2:1
  • Deduplication = 2:1
  • Daily change rate = 5%

After data reduction (compression & deduplication), the amount of data stored on the CBS instance for Volume_A is 25GB. 

If we start replicating this volume to a CBS instance located in the US-East-1 (N. Virginia) region at a “once per day” frequency, the initial baseline snapshot will transfer 25GB of data, and each subsequent snapshot will transfer 1.25GB of data (25GB X 5% = 1.25GB).

The cost of the initial replication will be $0.01/GB X 25GB = $0.25; after that, the daily cost of replicating a subsequent snapshot will be $0.01/GB X 1.25GB = $0.0125 (assuming that the amount of total egress is in the 1GB/month to 10TB/month range).

 

CloudSnap backup from CBS to Amazon S3 in the same AWS region

Data transferred between Amazon S3 and Amazon EC2 instances in the same AWS region is free. However, charges are incurred when requests are made to an S3 bucket during backup and restore processes. The Amazon S3 request charges are generally much lower than AWS data transfer charges, so users may choose to ignore them. If you wish to get an idea of the Amazon S3 request charges for CloudSnap backup and restore operations, please see appendix A.

 

CloudSnap backup from CBS to Amazon S3 in a different AWS region

When using CloudSnap to back-up data from CBS to an S3 bucket in a different AWS region, data transfer charges are applicable. Transferring data into an S3 bucket from another AWS region is free, but AWS charges are incurred for the outbound transfer of data from the source AWS region.

The data transfer cost of backing up data from a CBS instance in an AWS region to an S3 bucket in another region varies depending on the region in which the CBS instance is located. The following example shows the data transfer costs for backing up data from a CBS instance in the US-East-2 (Ohio) region (based on current prices):

  • The cost of moving data out of the US-East-2 (Ohio) region to the US-East-1 (N. Virginia) region is $0.01/GB
  • The cost of moving data out of the US-East-2 (Ohio) region to any AWS region other than the US-East-1 (N. Virginia) region is $0.02/GB

The link below has a complete list of the latest prices for data transfers between different AWS regions: 

https://aws.amazon.com/ec2/pricing/on-demand/

Example calculation

Let’s take the example of Volume_A again, located on a CBS instance in the US-East-2 (Ohio) region with the following properties:

  • Data size = 100GB
  • Compression = 2:1
  • Deduplication = 2:1
  • Daily change rate = 5%

After data reduction (compression & deduplication), the amount of data stored on the CBS instance for Volume_A is 25GB. 

If we start offloading this volume via CloudSnap to an S3 bucket located in the US-East-1 (N. Virginia) region at a “once per day” frequency, the initial baseline snapshot will transfer 50GB of data (the data is compressed, but not deduped), and each subsequent snapshot will transfer 2.5GB of data (50GB X 5% = 2.5GB).

The cost of the initial data transfer will be $0.01/GB X 50GB = $0.50; after that, the daily cost of transferring a subsequent snapshot will be $0.01/GB X 2.5GB = $0.025 (assuming that the amount of total egress is in the 1GB/month to 10TB/month range).

In addition to the above data transfer charges, Amazon S3 request charges also apply when using CloudSnap to backup data from a CBS instance to an S3 bucket in a different AWS region. The Amazon S3 request charges are generally much lower than data transfer charges, so users may choose to ignore them. If you wish to get an idea of the Amazon S3 request charges for CloudSnap backup and restore operations, please see appendix A.

 

CloudSnap restore from Amazon S3 to CBS in the same AWS region

Transfers from Amazon S3 to any service(s) within the same AWS Region are free. However, charges are incurred when requests are made to an S3 bucket during the transfer process. 

The Amazon S3 request charges are generally much lower than data transfer charges, so users may choose to ignore them. If you wish to get an idea of the Amazon S3 request charges for CloudSnap backup and restore operations, please see appendix A.

Lastly, if data is restored from the Amazon S3 Infrequent Access storage tier, there’s an additional data retrieval cost to pull data out. For the US-East-2 (Ohio) region, this is listed (in the last row, last column) in the table below:

 

 

PUT, COPY, POST, LIST requests (per 1,000 requests)

GET, SELECT, and all other requests (per 1,000 requests)

Data retrieval (per GB)

S3 Standard

$0.005

$0.0004

$0.00

S3 Infrequent Access

$0.01

$0.001

$0.01

 

To see a complete list of the current prices for all AWS regions, please visit this link:  

https://aws.amazon.com/s3/pricing/

 

CloudSnap restore from Amazon S3 to CBS in a different AWS region

Transferring data into a CBS instance from another AWS region is free; however, Data transfers out from Amazon S3 to a different AWS Region incur charges. The following example shows charges for data transfers from Amazon S3 in the US-East-2 (Ohio) region:

  • Data transfer out from Amazon S3 in US-East-2 (Ohio) to US-East-1 (N. Virginia) is $0.01/GB
  • Data transfer out from Amazon S3 in US-East-2 (Ohio) to all other AWS regions (other than US-East-1) is $0.02/GB

For the latest data transfer pricing for all AWS regions, please check out this link: https://aws.amazon.com/s3/pricing/

In addition, charges are incurred when requests are made to an S3 bucket during the transfer process. The Amazon S3 request charges are generally much lower than data transfer charges, so users may choose to ignore them. If you wish to get an idea of the Amazon S3 request charges for CloudSnap backup and restore operations, please see appendix A.

Lastly, if data is restored from the Amazon S3 Infrequent Access storage tier, there’s an additional data retrieval cost to pull data out. For the US-East-2 (Ohio) region, this is listed (in the last row, last column) in the table below:

 

 

PUT, COPY, POST, LIST requests (per 1,000 requests)

GET, SELECT, & all other requests (per 1,000 requests)

Data retrieval (per GB)

S3 Standard

$0.005

$0.0004

$0.00

S3 Infrequent Access

$0.01

$0.001

$0.01

 

To see a complete list of the current prices for all AWS regions, please visit this link:  

https://aws.amazon.com/s3/pricing/

 

 

Appendix A

When data is written to or read from an S3 bucket in AWS, request charges are incurred. Amazon S3 request charges are based on the request type, and are charged on the quantity of requests. Current Amazon S3 request charges for the US-East-2 (Ohio) region are listed in the table below:

 

 

PUT, COPY, POST, LIST requests (per 1,000 requests)

GET, SELECT, and all other requests (per 1,000 requests)

S3 Standard

$0.005

$0.0004

S3 Infrequent Access

$0.01

$0.001

 

DELETE and CANCEL requests are free. For a complete list of the latest Amazon S3 request charges for all AWS regions, please visit this link:  https://aws.amazon.com/s3/pricing/

Example calculation

Let’s take the example of Volume_A again, located on a CBS instance in the US-East-2 (Ohio) region with the following properties:

  • Data size = 100GB
  • Compression = 2:1
  • Deduplication = 2:1
  • Daily change rate = 5%

After data reduction (compression & deduplication), the amount of data stored on the CBS instance for Volume_A is 25GB. 

 

Amazon S3 request charges for transferring data to an S3 bucket

If we start offloading Volume_A via CloudSnap to an S3 bucket located within the US-East-2 (Ohio) region at a “once per day” frequency, the initial baseline snapshot will transfer 50GB of data (the data is compressed, but not deduped), and each subsequent snapshot will transfer 2.5GB of data (50GB X 5% = 2.5GB). The approximate number of Amazon S3 requests for offloading a 50G snapshot to an S3 bucket via CloudSnap are as follows:

  • PUT requests = 12,000
  • POST requests = 1,600

The number of requests listed above mayl vary depending on the data type. The number of LIST & GET requests during offload is so small that it can be ignored.

In this example, the total number of “PUT, COPY, POST, & LIST” requests is 13,600. Since the request charges are $0.005 per 1000 requests, for the initial baseline transfer, the total cost of Amazon S3 requests to offload a 50G snapshot to an S3 standard bucket is $0.005 X 14 = $0.07. The total number of Amazon S3 requests for offloading a subsequent 2.5G daily snapshot is less than a thousand, resulting in a cost of $0.005 X 1 = $0.005.

The Amazon S3 request charges for offloading data to an S3 Infrequent Access bucket in the US-East-2 (Ohio) region can be calculated in the same way. The request charges for an S3 Infrequent Access bucket are different, as listed in the table.

 

Amazon S3 request charges for restoring data from an S3 bucket

If we restore Volume_A via CloudSnap from an S3 bucket located in the US-East-2 (Ohio) region to the CBS instance from which the snapshot was offloaded, CloudSnap will only pull back the missing data blocks from the S3 bucket to rebuild the complete snapshot on CBS, reducing restore time and AWS costs. If Volume_A is restored from the S3 bucket in US-East-2 to a brand new CBS instance, the restore operation will transfer 50GB of data (the data is compressed, but not deduped). The approximate number of Amazon S3 requests for restoring the 50G snapshot from an S3 bucket via CloudSnap are as follows:

  • LIST requests = 600
  • GET requests = 13,700

The number of requests listed above will vary depending on the data type.

Since the request charges are $0.005 per 1000 LIST requests, and $0.0004 per 1000 GET requests, the total Amazon S3 request cost to restore the 50G snapshot is $0.005 X 1 + $0.0004 X 14 = $0.0106. 

The Amazon S3 request charges for restoring data from an S3 Infrequent Access bucket in the US-East-2 (Ohio) region can be calculated in the same way. The request charges for an S3 Infrequent Access bucket are different, as listed in the table.