You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
111 lines
5.3 KiB
111 lines
5.3 KiB
# MinIO Storage Class Quickstart Guide [](https://slack.min.io)
|
|
|
|
MinIO server supports storage class in erasure coding mode. This allows configurable data and parity disks per object.
|
|
|
|
## Overview
|
|
|
|
MinIO supports two storage classes, Reduced Redundancy class and Standard class. These classes can be defined using environment variables
|
|
set before starting MinIO server. After the data and parity disks for each storage class are defined using environment variables,
|
|
you can set the storage class of an object via request metadata field `x-amz-storage-class`. MinIO server then honors the storage class by
|
|
saving the object in specific number of data and parity disks.
|
|
|
|
## Storage usage
|
|
|
|
The selection of varying data and parity drives has a direct impact on the drive space usage. With storage class, you can optimize for high
|
|
redundancy or better drive space utilization.
|
|
|
|
To get an idea of how various combinations of data and parity drives affect the storage usage, let’s take an example of a 100 MiB file stored
|
|
on 16 drive MinIO deployment. If you use eight data and eight parity drives, the file space usage will be approximately twice, i.e. 100 MiB
|
|
file will take 200 MiB space. But, if you use ten data and six parity drives, same 100 MiB file takes around 160 MiB. If you use 14 data and
|
|
two parity drives, 100 MiB file takes only approximately 114 MiB.
|
|
|
|
Below is a list of data/parity drives and corresponding _approximate_ storage space usage on a 16 drive MinIO deployment. The field _storage
|
|
usage ratio_ is simply the drive space used by the file after erasure-encoding, divided by actual file size.
|
|
|
|
| Total Drives (N) | Data Drives (D) | Parity Drives (P) | Storage Usage Ratio |
|
|
|------------------|-----------------|-------------------|---------------------|
|
|
| 16 | 8 | 8 | 2.00 |
|
|
| 16 | 9 | 7 | 1.79 |
|
|
| 16 | 10 | 6 | 1.60 |
|
|
| 16 | 11 | 5 | 1.45 |
|
|
| 16 | 12 | 4 | 1.34 |
|
|
| 16 | 13 | 3 | 1.23 |
|
|
| 16 | 14 | 2 | 1.14 |
|
|
|
|
You can calculate _approximate_ storage usage ratio using the formula - total drives (N) / data drives (D).
|
|
|
|
### Allowed values for STANDARD storage class
|
|
|
|
`STANDARD` storage class implies more parity than `REDUCED_REDUNDANCY` class. So, `STANDARD` parity disks should be
|
|
|
|
- Greater than or equal to 2, if `REDUCED_REDUNDANCY` parity is not set.
|
|
- Greater than `REDUCED_REDUNDANCY` parity, if it is set.
|
|
|
|
Parity blocks can not be higher than data blocks, so `STANDARD` storage class parity can not be higher than N/2. (N being total number of disks)
|
|
|
|
Default value for `STANDARD` storage class is `N/2` (N is the total number of drives).
|
|
|
|
### Allowed values for REDUCED_REDUNDANCY storage class
|
|
|
|
`REDUCED_REDUNDANCY` implies lesser parity than `STANDARD` class. So,`REDUCED_REDUNDANCY` parity disks should be
|
|
|
|
- Less than N/2, if `STANDARD` parity is not set.
|
|
- Less than `STANDARD` Parity, if it is set.
|
|
|
|
As parity below 2 is not recommended, `REDUCED_REDUNDANCY` storage class is not supported for 4 disks erasure coding setup.
|
|
|
|
Default value for `REDUCED_REDUNDANCY` storage class is `2`.
|
|
|
|
## Get started with Storage Class
|
|
|
|
### Set storage class
|
|
|
|
The format to set storage class environment variables is as follows
|
|
|
|
`MINIO_STORAGE_CLASS_STANDARD=EC:parity`
|
|
`MINIO_STORAGE_CLASS_RRS=EC:parity`
|
|
|
|
For example, set `MINIO_STORAGE_CLASS_RRS` parity 2 and `MINIO_STORAGE_CLASS_STANDARD` parity 3
|
|
|
|
```sh
|
|
export MINIO_STORAGE_CLASS_STANDARD=EC:3
|
|
export MINIO_STORAGE_CLASS_RRS=EC:2
|
|
```
|
|
|
|
Storage class can also be set via `mc admin config` get/set commands to update the configuration. Refer [storage class](https://github.com/minio/minio/tree/master/docs/config#storage-class) for
|
|
more details.
|
|
|
|
*Note*
|
|
|
|
- If `STANDARD` storage class is set via environment variables or `mc admin config` get/set commands, and `x-amz-storage-class` is not present in request metadata, MinIO server will
|
|
apply `STANDARD` storage class to the object. This means the data and parity disks will be used as set in `STANDARD` storage class.
|
|
|
|
- If storage class is not defined before starting MinIO server, and subsequent PutObject metadata field has `x-amz-storage-class` present
|
|
with values `REDUCED_REDUNDANCY` or `STANDARD`, MinIO server uses default parity values.
|
|
|
|
### Set metadata
|
|
|
|
In below example `minio-go` is used to set the storage class to `REDUCED_REDUNDANCY`. This means this object will be split across 6 data disks and 2 parity disks (as per the storage class set in previous step).
|
|
|
|
```go
|
|
s3Client, err := minio.New("localhost:9000", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY", true)
|
|
if err != nil {
|
|
log.Fatalln(err)
|
|
}
|
|
|
|
object, err := os.Open("my-testfile")
|
|
if err != nil {
|
|
log.Fatalln(err)
|
|
}
|
|
defer object.Close()
|
|
objectStat, err := object.Stat()
|
|
if err != nil {
|
|
log.Fatalln(err)
|
|
}
|
|
|
|
n, err := s3Client.PutObject("my-bucketname", "my-objectname", object, objectStat.Size(), minio.PutObjectOptions{ContentType: "application/octet-stream", StorageClass: "REDUCED_REDUNDANCY"})
|
|
if err != nil {
|
|
log.Fatalln(err)
|
|
}
|
|
log.Println("Uploaded", "my-objectname", " of size: ", n, "Successfully.")
|
|
``` |