> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nebius.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Storage classes in Object Storage
Object Storage provides *storage classes* that control the cost and speed of storing and processing objects in storage depending on desired access patterns. You can set the default storage class for each bucket and explicitly upload an object to a specific class.
## How to choose storage classes for your objects
Two storage classes are available:
* **Standard** (`STANDARD` for CLIs and tools) for low-cost unlimited capacity object storage.
* **Enhanced Throughput** (`ENHANCED_THROUGHPUT`) for storage that requires high bandwidth and low latency access.
The Enhanced Throughput storage class differs from the Standard class in the following ways:
* Unthrottled upload and download speed for Enhanced Throughput. In contrast, the upload and download speed for objects of the Standard class is limited to 20 GBps per tenant in each [region](../overview/regions). The same limit applies when a transition [lifecycle rule](/object-storage/objects/lifecycles) moves objects to or from the Standard storage class. This means that during lifecycle transitions, the upload/download speed via the S3 API may be reduced.
* 2x latency improvement (on larger objects) and 4x throughput improvement per a GiB of stored data compared to Standard class (when the bucket and the client are in the same Nebius AI Cloud region).
* You pay a higher price for storage size, but all operations and data egress are free. See the detailed cost breakdown in [Pricing in Object Storage](./resources/pricing).
You may find the Enhanced Throughput storage class useful in the following scenarios:
* Stream processed datasets or model weights to GPU.
* Write or read checkpoints.
* Provide a destination for an extract, transform and load process (ETL) that requires high throughput.
## How to set a default storage class for a bucket
Each bucket has a default storage class. All new objects are uploaded into this class unless you [explicitly define the class](#how-to-upload-an-object-to-a-storage-class).
By default, new buckets use the Standard storage class. You can change the default storage class both when you create a bucket and for an existing bucket. The new default storage class does not affect objects that are already in storage in the bucket.
You can use the **Force storage class** (`--force-storage-class`) [bucket parameter](/object-storage/buckets/manage#bucket-parameters) to make the default storage class override the storage class that you explicitly select for any individual object uploaded to the bucket.
### For a new bucket
1. In the sidebar, go to **Storage** → **Object Storage**.
2. Click **Create bucket**.
3. Select the storage class in the bucket creation form.
4. Configure the other settings and create the bucket.
When you [create a bucket](./buckets/manage), add the `--default-storage-class` parameter to set the default storage class:
```bash theme={null}
nebius storage bucket create \
--default-storage-class \
...
```
### For an existing bucket
1. In the sidebar, go to **Storage** → **Object Storage**.
2. Select the bucket you need and switch to the **Settings** tab.
3. Select the storage class and save the changes.
When you [modify a bucket](./buckets/manage#how-to-modify-buckets), set the `--default-storage-class` parameter:
```bash theme={null}
nebius storage bucket update \
--default-storage-class \
...
```
## How to upload an object to a storage class
If you need to store an object in a different storage class than the default one for the bucket, set the storage class during upload.
The [AWS CLI](/object-storage/interfaces/aws-cli) does not support uploading objects to a storage class that differs from the bucket's default. To do that, use [s5cmd](https://github.com/peak/s5cmd).
To [upload an object](./objects/upload-download#how-to-upload) to the desired storage class, set the `--storage-class` parameter in the upload command:
```bash s5cmd theme={null}
s5cmd cp \
--storage-class \
...
s3:///
```
To change the storage class of an object after you upload it, make a `copy-object` request that moves the object between storage classes:
```bash s5cmd theme={null}
s5cmd cp \
--storage-class \
...
s3:/// s3:///
```