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While this loads — worth knowing
ElastiCache RedisnotElastiCache Memcached
Redis has data structures — sorted sets, counters, pub/sub. Memcached has plain keys and nothing else.
Loading…
While this loads — worth knowing
Redis has data structures — sorted sets, counters, pub/sub. Memcached has plain keys and nothing else.
Three S3 storage classes for archives: Instant Retrieval, read in milliseconds; Flexible Retrieval, restored in minutes to hours; and Deep Archive, the lowest cost, restored within 12 to 48 hours.
Where S3 Glacier takes you5 steps, all open
The S3 Glacier storage classes keep data you rarely read at the lowest storage costs S3 has. The objects stay in your S3 bucket, designed for the same eleven nines of durability and stored across at least three Availability Zones. What changes is how quickly you can read them back, and what you pay when you do.
Three classes. Instant Retrieval returns an object in milliseconds, like S3 Standard. Flexible Retrieval and Deep Archive are archived: an object must be restored before it can be read, which takes minutes to hours from Flexible Retrieval and up to 48 hours from Deep Archive.
The original Amazon Glacier service, with vaults and an API of its own, no longer accepts new customers. AWS recommends these storage classes instead.
A storage warehouse offers a locker by the entrance that you open any time, a unit at the back that staff fetch within hours, or within minutes for a fee, and deep storage off-site that comes back within two days. The further away a box is kept, the less it costs to keep, and the more it costs to fetch.
Glacier Instant RetrievalGlacier Flexible RetrievalGlacier Deep ArchiveRestoreExpedited, Standard, BulkMinimum storage durationFlexible Retrieval and Deep Archive objects are archived and cannot be read in real time. Instant Retrieval needs no restore at all.
Asks for a temporary copy for a number of days.
Expedited, Standard or Bulk. Deep Archive has no Expedited tier.
Readable for the days you asked for, while the object itself stays in its archive class.
Pick a case to follow the restore through each check.
The waterfall only runs downhill. From Flexible Retrieval a Lifecycle rule can move objects only to Deep Archive, and from Deep Archive nowhere. To bring an object back up, restore it and copy it into another class.
Small objects stay put. Objects smaller than 128 KB are not transitioned by default, because every transition is a charged request and small objects save little.
Expire at the end. An expiration action in the same configuration deletes each report when its retention period is over.
Object Lock for write-once storage. On a versioned bucket, a retention period or a legal hold stops an object version being overwritten or deleted. In compliance mode nobody can shorten it, not even the root user; in governance mode, users with a special permission can.
Encryption carries over. Encrypted objects stay encrypted through every transition.
A bucket policy cannot stop Lifecycle. Even a policy that denies everything does not prevent a Lifecycle rule transitioning or deleting objects, so guard who can change the rules.
The same access control as the rest of S3. Archived objects are S3 objects, reached only through the S3 console and API, under the bucket's policies and Block Public Access.
Storage by the GB-month, lowest in Deep Archive. Each object in Flexible Retrieval or Deep Archive also carries 40 KB of metadata: 8 KB charged at S3 Standard rates and 32 KB at the class's own.
Retrieval by the GB, more for Expedited. Bulk retrieval from Flexible Retrieval is free.
Minimum storage durations. Delete, overwrite or move an object within 90 days, or 180 for Deep Archive, and you pay for the rest of the period. Instant Retrieval also bills every object as at least 128 KB.
Transition requests are charged for each object, which is why small objects are not transitioned by default.
While an object is restored, you pay for both the archived object and its temporary copy.
Prices change, so none are printed here. Check the S3 pricing page on aws.amazon.com.
| Class | First byte | Minimum duration | Availability | Choose it when |
|---|---|---|---|---|
| Glacier Instant Retrieval | Milliseconds | 90 days | 99.9% | Read about once a quarter, but at once |
| Glacier Flexible Retrieval | Minutes to hours, after a restore | 90 days | 99.99% after a restore | Backups and disaster recovery that can wait |
| Glacier Deep Archive | Within 12 or 48 hours, after a restore | 180 days | 99.99% after a restore | Compliance archives kept 7 to 10 years or longer |
| S3 Standard-IA | Milliseconds | 30 days | 99.9% | Read about once a month |
| S3 Intelligent-Tiering | Milliseconds, unless an archive tier is turned on | None | 99.9% | Access patterns unknown or changing |
| Retrieval tier | Flexible Retrieval | Deep Archive |
|---|---|---|
| Expedited | 1 to 5 minutes, for objects under 250 MB | Not available |
| Standard | 3 to 5 hours | Within 12 hours |
| Bulk | 5 to 12 hours, and free | Within 48 hours |
kept for ten years, almost never read, a request can wait two days, lowest costS3 Glacier Deep Archive
The lowest-cost class, with Standard restores within 12 hours and Bulk within 48.
archive data that must still come back in millisecondsS3 Glacier Instant Retrieval
No restore is needed: a GET returns it at once.
an archived file is needed urgently, within minutesExpedited retrieval from Flexible Retrieval
Typically 1 to 5 minutes for objects under 250 MB. Deep Archive has no Expedited tier.
Expedited retrievals must be accepted even at busy timesProvisioned capacity
Without it, Expedited requests may not be accepted when demand is high.
restore millions of archived objectsS3 Batch Operations
One job restores them all at the rate the account allows.
archived objects deleted after a month were charged for threeThe minimum storage duration
Deleting early is charged for the remaining days: 90 for Instant and Flexible Retrieval, 180 for Deep Archive.
WORM storage that even the root user cannot delete earlyObject Lock in compliance mode
No user can shorten or remove its retention period.
a restored object still shows its Glacier storage classA restore is a temporary copy
The object stays in its archive class. Copy it to change the class.
archiving millions of tiny files costs more than expectedBundle small files into larger objects
Every archived object carries 40 KB of metadata and a charged transition request.
A hospital must keep scanned records for 10 years. They are almost never read, but when a request for one arrives, the hospital has 72 hours to answer it. The storage must cost as little as possible. Which S3 storage class should it use?
A nightly job writes reports to an S3 bucket. After 90 days they are almost never read, but they must be kept for ten years at the lowest cost, and a request for one can wait up to two days. Where should a Lifecycle rule move them?
90 days minimum.180 days minimum.128 KB stays put by default.40 KB of metadata on every archived object.This whole page is free right now.The AWS library is still being written, so every page of it is open to everyone while that lasts. It becomes a paid bundle later; what you read today costs you nothing.
Every fact on this page was checked against AWS’s own documentation on 15 Sept 2026. If AWS has changed something since, its page is the one to trust.