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Erasure Code Settings
minio
Table of Contents
This page covers settings that configure the Erasure Code <minio-erasure-coding> parity <minio-ec-parity> to use for objects
written to the MinIO cluster. This impacts how MinIO uses the space on
the drive(s) and how MinIO can recover objects stored on lost drives or
similar issues.
Note
MinIO Storage Classes are distinct from AWS Storage Classes.
AWS Storage Classes refer to the specific storage tier on which to
store a given object, such as hot or glacier
storage. MinIO Storage Classes affect the erasure code parity setting
used and relate to minio-availability-resiliency of objects.
For tiering from one type of storage to another, such as for cost
management purposes, see minio-lifecycle-management-tiering.
Define any of these environment variables in the host system prior to starting or restarting the MinIO process. Refer to your operating system's documentation for how to define an environment variable.
Environment Variables
Note
These settings do not have configuration setting options for use with
mc admin config set.
MINIO_STORAGE_CLASS_STANDARD
The parity level <minio-ec-parity> for the
deployment. MinIO shards objects written with the default
STANDARD storage class using this parity value.
MinIO references the x-amz-storage-class header in
request metadata for determining which storage class to assign an
object. The specific syntax or method for setting headers depends on
your preferred method for interfacing with the MinIO server.
Specify the value using EC:M notation, where
M refers to the number of parity blocks to create for the
object.
The following table lists the default values based on the erasure set size <minio-ec-erasure-set> of the
initial server pool in the deployment:
| Erasure Set Size | Default Parity (EC:N) |
|---|---|
| 1 | EC:0 |
| 2-3 | EC:1 |
| 4-5 | EC:2 |
| 6 - 7 | EC:3 |
| 8 - 16 | EC:4 |
The minimum supported value is 0, which indicates no
erasure coding protections. These deployments rely entirely on the
storage controller or resource for availability / resiliency.
The maximum value depends on the erasure set size of the initial server pool in the deployment, where the upper bound is $\frac{\text{ERASURE_SET_SIZE}}{\text{2}}$. For example, a deployment with erasure set stripe size of 16 has a maximum standard parity of 8.
You can change this value after startup to any value between
0 and the upper bound for the erasure set size. MinIO only
applies the changed parity to newly written objects. Existing objects
retain the parity value in place at the time of their creation.
MINIO_STORAGE_CLASS_RRS
The parity level <minio-ec-parity> for objects
written with the REDUCED storage class.
MinIO references the x-amz-storage-class header in
request metadata for determining which storage class to assign an
object. The specific syntax or method for setting headers depends on
your preferred method for interfacing with the MinIO server.
Specify the value using EC:M notation, where
M refers to the number of parity blocks to create for the
object.
This value must be less than or equal to MINIO_STORAGE_CLASS_STANDARD.
You cannot set this value for deployments with an erasure set size
less than 2. Defaults to EC:1 for deployments with erasure
set size greater than 1. Defaults to EC:0 for deployments
of erasure set size of 1.
MINIO_STORAGE_CLASS_COMMENT
Adds a comment to the storage class settings.