Discuss EFS lifecycle properties.
EFS Lifecycle Management automatically moves files between storage classes based on access patterns. Using configurable lifecycle policies, files not accessed for a defined period are transitioned from the Standard (or One Zone) class to the lower-cost Infrequent Access (IA) class, and can be transitioned back when accessed again.
EFS Lifecycle Management works similarly to S3 Intelligent-Tiering. You define policies that specify when a file should be transitioned to a cheaper storage class and when it should be moved back. AWS EFS monitors the last-accessed timestamp of every file and automatically moves files according to your policy. This can reduce storage costs by up to 92% for files that are rarely accessed, without requiring any changes to your application.
- 1
Controls when files are moved FROM Standard (or One Zone) TO the Infrequent Access (IA) class
- 2
Available thresholds: After 1 day, 7 days, 14 days, 30 days, 60 days, or 90 days since last access
- 3
Example: 'Transition to IA after 30 days' — any file not accessed in 30 days is automatically moved to Standard-IA
- 4
The transition happens in the background with no downtime or application change required
- 5
Files smaller than 128 KB are NOT transitioned — the overhead of moving tiny files outweighs the savings
- 6
Metadata (file name, permissions, timestamps) remains in the Standard class regardless of where the data is stored
- 1
Controls when files are moved FROM Infrequent Access BACK TO the Standard (or One Zone) class
- 2
Available options: On first access (immediately move back when a file is read)
- 3
This is optional — if you do not configure it, files stay in IA even after being accessed
- 4
Recommended for workloads where accessing a file signals that it will be accessed frequently again
- 5
Not recommended for analytics workloads that do one-time full-scan reads — files would all move back to Standard, increasing costs
- 1
EFS Standard costs approximately $0.30 per GB-month
- 2
EFS Standard-IA costs approximately $0.025 per GB-month — 92% cheaper
- 3
EFS One Zone costs approximately $0.16 per GB-month
- 4
EFS One Zone-IA costs approximately $0.0133 per GB-month — 95% cheaper than Standard
- 5
A typical file system where 80% of files are infrequently accessed can see 60–70% overall cost reduction with lifecycle policies enabled
- 6
There is a per-GB retrieval fee when accessing IA files — optimize by only moving back files that will be accessed repeatedly
Scenario Questions
0-2 years experience
- 1You have log files that are accessed heavily for the first week and then rarely. How would you set up an EFS lifecycle policy to lower costs?
- 2What happens to a file when you configure a 30‑day transition policy on an EFS file system?
- 3If you delete a file that has already been moved to the IA storage class, what does EFS do?
2-5 years experience
- 1Your application started seeing higher read latency after you enabled an EFS lifecycle policy. How would you troubleshoot the root cause?
- 2Explain the trade‑offs between using a 7‑day versus a 30‑day transition policy for a data‑processing pipeline that writes temporary files to EFS.
- 3You notice that your backup job fails because it expects files in the Standard class, but they have been moved to IA. How would you adjust the lifecycle configuration?
5-8 years experience
- 1Design a multi‑AZ architecture that uses EFS with lifecycle policies to serve both hot and cold data for a media processing service. What performance, cost, and durability considerations would you make?
- 2At petabyte scale, how does the EFS lifecycle transition affect throughput, and what mitigations would you put in place?
- 3If regulatory rules require certain files never transition to IA, how would you implement exceptions in the lifecycle policy?
8+ years experience
- 1Your organization is migrating legacy on‑prem NFS shares to EFS and wants lifecycle policies that differ per business unit. How would you design a governance model and automation to enforce consistent policies while allowing unit‑level overrides?
- 2Discuss the long‑term operational impact of using EFS lifecycle policies on data‑analytics workloads that need predictable latency, and how you would mitigate any risks.
- 3How would you evaluate whether to keep cold data in EFS IA versus moving it to S3 Glacier, considering cost, access patterns, and cross‑team responsibilities?
Follow-up Questions
- What metrics would you watch to confirm the policy is working as expected?
- How would you test the impact on latency before rolling the policy out to production?
- If a compliance requirement says certain files must never move to IA, how would you enforce that?