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Storage Classes

When storing data on-premise a PACS system will use some form of hardware like a NAS or SAN to hold that data. There may also be other storage in use like tapes for long term offline archiving. The amount of storage that's required needs to be estimated in advance and purchased up front even when the capacity may not be needed for a long period of time. When that storage capacity is eventually depleted or needs replacement a lengthy process of migration is required to move it all onto new storage.

However, when it comes to AdvaPACS, your data is stored using object storage which is conceptually different from traditional storage mediums. This storage method allows you to pay only for the storage capacity you actually use, in contrast to on-premise storage where significant upfront costs are necessary for purchasing and installing storage hardware.

With object storage there are a few key differences in how you need to think about your data. It's no longer just about how much data you need to store, but how you are accessing that data. When considering which AdvaPACS Storage Classes are right for your workload, you should consider;

  1. How much data do I need to store?
  2. How long do I need to store the data for?
  3. How often do I need to access the data?
  4. Do I need to access the data at short notice? (< 12 hours)

The costs associated with storing and retrieving data in AdvaPACS vary by Storage Class.

AdvaPACS offers four Storage Classes:

  • Online
  • Online - Infrequent Access
  • Nearline
  • Offline (coming soon)

These conceptually equate to the DICOM Instance Availability specification.

Configuring Storage Classes​

Storage Classes are configured per Local AE. As you have the capability to create multiple Local AEs within an AdvaPACS Gateway, you can establish different Local AEs, each possibly associated with different Storage Classes.

The Storage Class can also be dynamically set per Series or Study from within an Upload Rule.

Pricing​

The pricing for each Storage Class varies, and the best option will be determined by how you intend to use AdvaPACS.

To check the pricing for the Storage Classes, navigate to Local AEs -> Advanced Configuration and click the ? next to the Storage Class option.

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Prices will vary region to region due to differences in the pricing by the underlying cloud provider.

Pricing Dimensions​

Minimum Storage Retention​

The minimum period of time data can be stored in this Storage Class. If you delete a file before this period of time has elapsed you will be charged for the remaining amount of time.

Storage Cost (GiB/month)​

The amount you will be charged to store 1 GiB of data each month.

Get Request​

The price to GET a file from this storage class. This will occour each time the file is read. For example, viewing an instance.

Put Request​

The price to PUT a file into this Storage Class. This will occour each time a file is uploaded. For example, uploading an instance.

Data Retrieval Request​

For each Study or Series triggered for restore from Offline.

Data Retrieval (GiB)​

For each GiB of data read from the Storage Class.

Pricing Examples​

For the following pricing examples, the prices have been set to easy to calculate numbers. If you wish to do your own calculations, you can get the pricing that will apply to your AdvaPACS from Local AEs -> Advanced Configuration -> Storage Class -> ?.

Example 1 : X-Ray​

You wish to store an X-Ray in AdvaPACS for 10 years. The X-Ray is 20MiB in size and consists of 3 views. The X-Ray will be viewed 3 times over this period. It will be stored in the Online Storage Class.

Storage Costs for 10 years: $0.025 0.02 12 10 = $0.06 Put Request Cost: ($0.0055/1000) 3 = $0.0000165 Get Request Cost: ($0.0055/1000) 3 3 = $0.00000396

Total cost: $0.06002046

Now if we assume that we store this in the Nearline Storage Class

Storage Costs for 10 years: $0.005 0.02 12 10 = $0.012 Put Request Cost: ($0.02/1000) 3 = $0.00006 Get Request Cost: ($0.01/1000) 3 3 = $0.00009

Total cost: $0.01215

Example 2 : CT​

You wish to store a CT in AdvaPACS for 10 years. The CT is 600MiB in size and consists of 1200 instances. The CT will be viewed 2 times over this period. It will be stored in the Online - Infrequent Access Storage Class.

Storage Costs for 10 years: $0.014 0.6 12 10 = $1.008 Put Request Cost: ($0.01/1000) 1200 = $0.012 Get Request Cost: ($0.001/1000) 1200 2 = $0.0024 Data Retrieval Cost: $0.01 0.6 2 = $0.012

Total cost: $1.0344

Now if we assume that we store this in the Nearline Storage Class

Storage Costs for 10 years: $0.005 0.6 12 10 = $0.36 Put Request Cost: ($0.02/1000) 1200 = $0.024 Get Request Cost: ($0.01/1000) 1200 2 = $0.024 Data Retrieval Cost: $0.03 0.6 2 = $0.036

Total cost: $0.444