EFS Cost Savings and Lifecycle Implementation - FAQ
Clix Capital AWS Ticket Reference CASE 12862852571
1.In EFS metadata write cost is one time cost?
Answer:
If the CX using Elastic Throughput, Then it'll be charged per GB transferred for Metadata writes.
For an example if the filesystem is in us-east-2 region with Elastic Throughput mode, then, the metadata write costs would be $0.06 per GB transferred (additionally to the Storage cost)
Ref: https://aws.amazon.com/efs/pricing/
If the CX using Provisioned Throughput, then they'll be additionally paying for Throughput value that they set. Again for Ohio region it'll be $6.00 per configured value (in MB/s), per Month.
If the CX using Bursting Throughput, then is no exclusive charges, as they utilizing burst credits with all reads/writes. (still the storage cost will be there)
2.Unlike S3, there is no need to check the average file size or file count to determine the transition cost?
Answer:
There is no transition cost with in storage classes. (https://aws.amazon.com/efs/features/infrequent-access/)
However there is a charge for access requests which is calculated by per GB transferred.
For Ohio region it'll be $0.01 per GB transferred.
Refer Infrequent Access Requests (per GB transferred) in https://aws.amazon.com/efs/pricing/
3.For file transition, only metadata write cost is applicable?
Answer:
IA access charges are only for data, not metadata (Metadata access is metered as throughout. But because it is so small it wouldn't be much)
4.Is there any delay in file retrieval/access from IA storage class?
Answer:
Yes. Compared to Standard Storage class, IA storage class have more latency on file access.
5.Cost savings with assumption, 1TB out of 10 TB data is transitioned to IA after applying the policy?
Answer:
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Below charges are for US East (Ohio) region:
++Before: 10 TB in Standard++:
Total EFS Standard Storage usage (GB-Hours): 10,000 GB x 31 days x (24 hours / day) = 7,440,000 GB-Hours
We add up GB-Hours and convert to GB-Month to calculate monthly charges:
Total EFS Standard storage charge: 7,440,000 GB-Hours x (1 month / 744 hours) x $0.30/GB-month = $3000.00
++After: 9TB in Standard, and 1TB in IA storage++:
Total EFS Standard Storage usage (GB-Hours): 9000 GB x 31 days x (24 hours / day) = 6,696,000 GB-Hours
Total EFS IA Storage usage (GB-Hours): 1000 GB x 31 days x (24 hours / day) = 744,000 GB-Hours
We add up GB-Hours and convert to GB-Month to calculate monthly charges:
Total EFS Standard storage charge: 6,696,000 GB-Hours x (1 month / 744 hours) x $0.30/GB-month = $2700.00
Total EFS Standard-IA storage charge: 744,000 GB-Hours x (1 month / 744 hours) x $0.025/GB-month = $25.00
Total Monthly Storage Charge: $2700.00 + $25.00 = $2725.00
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Ref: Example 2 of https://aws.amazon.com/efs/pricing/