EFS Infrequent Access cost: cutting file storage by 90 percent

Quick answer

EFS Standard storage costs about $0.30 per GB-month in us-east-1, while EFS Standard-Infrequent Access (IA) costs about $0.016 per GB-month, a roughly 95 percent reduction, plus a $0.01 per GB access charge each time an IA file is read. EFS Lifecycle Management moves files not accessed within a set window (7 to 90 days) to IA automatically, and Intelligent-Tiering moves them back to Standard if they become active again. Because most file systems have a long tail of cold files, enabling lifecycle management typically cuts an EFS bill by 60 to 90 percent with no application change.

EFS is one of the more expensive ways to store data on AWS: Standard storage is about $0.30 per GB-month, roughly 13 times the price of S3 Standard, because it is a fully managed, elastic, multi-AZ POSIX file system. That price is justified for hot, actively-shared files, but most EFS file systems accumulate a large tail of files that are rarely touched after creation. The Infrequent Access tier exists to store exactly those for a fraction of the cost.

The storage tiers and their prices

Tier	Storage /GB-mo	Access fee
Standard	~$0.30	none
Standard-IA	~$0.016	~$0.01 per GB read
One Zone	~$0.16	none
One Zone-IA	~$0.0133	~$0.01 per GB read

The IA tiers cut storage cost by about 95 percent, from $0.30 to $0.016 per GB on Standard-IA. The trade-off is a $0.01 per GB access charge each time an IA file is read, and slightly higher first-byte latency. For genuinely cold files that is a great deal; for files read often it is a bad one, because the access fees pile up. The whole game is making sure only truly infrequently-accessed data lands in IA.

Lifecycle management does the sorting

EFS Lifecycle Management handles the tiering automatically. You set a policy such as move files not accessed for 30 days to IA, and EFS transitions cold files without any application change. Paired with Intelligent-Tiering, EFS also moves files back to Standard if they start being accessed regularly again, so you get the IA saving on cold data without paying repeated access fees on data that turned hot. This automatic, bidirectional tiering is what makes EFS IA safe to enable broadly.

What the saving looks like

Consider a 10 TB file system where 8 TB is cold. On all-Standard, that is 10,240 GB at $0.30, about $3,072 per month. With lifecycle management moving the 8 TB to IA, the cold data costs 8,192 GB at $0.016, about $131, while the hot 2 TB stays at $0.30 for about $614, totaling roughly $745. That is a 76 percent reduction from a single configuration change, before considering the occasional access fees on the cold data. For most file systems the cold tail is large, so the saving is dramatic.

Throughput and One Zone add more levers

Storage is only part of EFS cost; throughput mode matters too, and Elastic throughput bills per data transferred rather than provisioned, as covered in EFS throughput modes. For data that does not need multi-AZ resilience, One Zone and One Zone-IA cut storage roughly in half again. And for workloads where a file system is the wrong tool entirely, compare against block and object storage in EFS versus EBS and EFS versus EBS versus S3.

Enable lifecycle by default

EFS is expensive at the Standard rate and cheap at the IA rate, and lifecycle management bridges the two automatically with almost no downside for cold data. Turn on lifecycle management with a sensible transition window and Intelligent-Tiering on essentially every EFS file system, choose One Zone where resilience allows, and price the file system and its tiering configuration against the resource catalog before deploy so the cold tail lands in IA from the start rather than sitting at 13 times the price on Standard.

FAQ

How much does EFS Infrequent Access cost?

EFS Standard-Infrequent Access is about $0.016 per GB-month in us-east-1, versus about $0.30 for EFS Standard, a roughly 95 percent reduction. Reading an IA file adds a $0.01 per GB access charge. One Zone-IA is cheaper still at about $0.0133 per GB. The IA tiers are ideal for cold files but costly for frequently-read data due to the access fees.

How does EFS lifecycle management save money?

It automatically moves files not accessed within a set window (7 to 90 days) from Standard to Infrequent Access, cutting their storage cost by about 95 percent with no application change. Paired with Intelligent-Tiering, it also moves files back to Standard if they become active again, so you avoid repeated access fees on data that turned hot.

How much can EFS IA reduce my bill?

Typically 60 to 90 percent, because most file systems have a large cold tail. A 10 TB file system with 8 TB cold costs about $3,072 per month all-Standard, but roughly $745 with lifecycle management moving the cold 8 TB to IA, a 76 percent cut from one configuration change, before occasional access fees on the cold data.

When is EFS IA a bad choice?

For frequently-read files. The $0.01 per GB access charge on every IA read means hot data accessed often accumulates access fees that can exceed the storage saving. Lifecycle management with Intelligent-Tiering avoids this by keeping active files on Standard and only moving genuinely cold files to IA, which is why automatic tiering is safer than forcing IA manually.

How does C3X help with EFS cost?

C3X prices EFS file systems from Terraform including storage class, throughput mode, and lifecycle configuration, so whether lifecycle management and Intelligent-Tiering are enabled is visible in the pull request. That prompts teams to turn on automatic tiering at design time, ensuring the cold tail lands in IA from the start rather than sitting at 13 times the price on Standard.

What to do next

Let cold files fall to the cheap tier automatically. C3X prices EFS and its lifecycle configuration from Terraform against a live resource catalog. Start with the quickstart.