# Initialize Amazon EBS volumes
When you create an Amazon EBS volume, either from an EBS snapshot or from another EBS volume (volume copy), the data blocks must be written to the volume before you can access them. For volumes created from snapshots, the data blocks must be downloaded from Amazon S3 to the new volume. For volume copies, the data blocks must be copied from the source volume to the volume copy. This process is called *volume initialization*. During this time, the volume being initialized might experience increased I/O latency and decreased performance. Full volume performance is achieved only once all storage blocks have been downloaded and written to the volume.
**Note**
Empty volumes deliver their maximum performance immediately after creation and do not require initialization.
The default volume initialization rate fluctuates throughout the initialization process, which could make completion times unpredictable. To minimize the performance impacts associated with volume initialization, you could use the following options:
**Note**
Volume initialization rate and fast snapshot restore are not supported for volume copies. For more information, see [Volume copy initialization](ebs-copying-volume.md#copy-volume-initialization).
**Topics**
+ [
## Use an Amazon EBS Provisioned Rate for Volume Initialization
](#volume-initialization-rate)
+ [
## Use a snapshot that is enabled for fast snapshot restore
](#volume-initialization-fsr)
+ [Manually initialize volumes](#ebs-initialize)
+ [Monitor volume initialization](ebs-initialize-monitor.md)
## Use an Amazon EBS Provisioned Rate for Volume Initialization
When you create an Amazon EBS volume from a snapshot, you can optionally specify an Amazon EBS Provisioned Rate for Volume Initialization (volume initialization rate) that ranges from 100 to 300 MiB/s. If you specify a volume initialization rate, the snapshot blocks are downloaded from Amazon S3 and written to the volume at the specified rate after creation. This enables you to create volumes that become fully initialized and fully performant in a predictable amount of time.
Using a volume initialization rate is especially useful when you are creating multiple volumes simultaneously and you need all of them to be initialized in a predictable amount of time.
**Note**
Amazon EBS Provisioned Rate for Volume Initialization is supported with all Amazon EBS volume types, and all Amazon EC2 instance types, including Amazon EC2 Mac instances.
You can specify a volume initialization rate:
+ For individual volume creation requests
+ For EBS volume block device mappings in instance launch requests
+ For EBS volume block device mappings in launch templates
+ For EBS volumes created by root volume replacement tasks
+ For EBS volumes on Amazon EKS clusters (created by EBS CSI Driver) and Amazon ECS clusters
**Topics**
+ [
### How it works
](#consistent-rate-how)
+ [
### Considerations
](#consistent-rate-considerations)
+ [
### Quotas
](#consistent-rate-quota)
+ [
### Billing
](#consistent-rate-billing)
### How it works
When you create a volume with a volume initialization rate, the snapshot blocks are downloaded from Amazon S3 to the volume at the rate you specify.
The amount of time taken to initialize the volume depends on the following:
+ The size of the snapshot data, not the size of the volume being created.
**Tip**
To find a snapshot's data size, check the `FullSnapshotSizeInBytes` field in the [ describe-snapshots](https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-snapshots.html) command output, or the **Full snapshot size** field in the console.
+ The volume initialization rate that you specify
For example, if you create a 20 GiB volume using a snapshot that has 10 GiB of data, and you specify a volume initialization rate of 300 MiB/s, the volume will be fully initialized in approximately 34.1 seconds (10 GiB / 300 MiB/s = 34.1 seconds). Similarly, if you create 10 volumes with that same snapshot and volume initialization rate concurrently, all 10 volumes will be fully initialized in 34.1 seconds.
### Considerations
+ You can specify a volume initialization rate of between 100 and 300 MiB/s.
+ When you specify a volume initialization rate, the charges and completion time are based on the size of the snapshot data (not the size of the volume) and the rate you specify. For more information, see [Billing](#consistent-rate-billing).
+ Amazon EBS delivers an average rate that is within 10 percent of the volume initialization rate that you specify for 99 percent of the time.
+ If you specify a volume initialization rate and use a snapshot that is enabled for fast snapshot restore, Amazon EBS uses the specified rate instead of fast snapshot restore. To use fast snapshot restore instead, do not specify a volume initialization rate.
+ If Amazon EBS can't initialize the volume at the specified volume initialization rate due to capacity constraints or because you have exceeded your [ quota](#consistent-rate-quota), the request fails.
+ You can't specify a volume initialization rate for volumes created on AWS Outposts, or in Local Zones or Wavelength Zones.
### Quotas
There is a limit of 5,000 MiB/s on the cumulative volume initialization rate that you can request across concurrent volume creation requests. For example, you can make 50 concurrent volume creation requests with a rate of 100 MiB/s (50 simultaneous requests \$1 100 MiB/s rate), or 25 concurrent requests with a rate of 200 MiB/s (25 simultaneous requests \$1 200 MiB/s rate). This limit applies on a per Region basis. If a request exceeds this limit, it fails. Either wait for some of the in-progress requests to complete or request a quota increase. For more information, see [Quotas for Amazon EBS](ebs-resource-quotas.md).
### Billing
When you create a volume with a volume initialization rate, you are charged a rate per GiB of snapshot data, per MiB of specified initialization rate. The rate varies by Region. For more information, see [Amazon EBS pricing](https://aws.amazon.com/ebs/pricing/).
You are charged based on the size of the snapshot data, not the size of the volume. For example, if you create a snapshot of a volume that is 100 GiB in size, but has only 50 GiB of data, the snapshot has a volume size of 100 GiB, but the snapshot data size is 50 GiB. If you use that snapshot to create a volume and specify a volume initialization rate, your charges are based on the 50 GiB of snapshot data.
**Tip**
To find a snapshot's data size, check the `FullSnapshotSizeInBytes` field in the [ describe-snapshots](https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-snapshots.html) command output, or the **Full snapshot size** field in the console.
The formula is as follows:
```
rate for Region x snapshot data size x volume initialization rate
```
You are billed the full amount as soon as the volume enters the `active` state. Failed requests are not billed.
If you delete a volume before the volume initialization completes, you are still billed for the requested volume initialization rate.
## Use a snapshot that is enabled for fast snapshot restore
If you create a volume from a snapshot that is enabled for fast snapshot restore, the volume is fully initialized at creation and it immediately delivers its full performance. For more information about using fast snapshot restore, see [Amazon EBS fast snapshot restore](ebs-fast-snapshot-restore.md).
## Manually initialize the volumes after creation
You can manually initialize an Amazon EBS volume after creation to help minimize the performance impacts of volume initialization.
You can use the following procedures to manually initialize an Amazon EBS volume after creation.
**Important**
While initializing Provisioned IOPS SSD volumes that were created from snapshots, the performance of the volume may drop below 50 percent of its expected level, which causes the volume to display a `warning` state in the **I/O Performance** status check. This is expected, and you can ignore the `warning` state on Provisioned IOPS SSD volumes while you are initializing them. For more information, see [Amazon EBS volume status checks](monitoring-volume-checks.md).
### Linux instances
**To initialize a volume created from a snapshot on Linux**
1. Attach the newly-restored volume to your Linux instance.
1. Use the **lsblk** command to list the block devices on your instance.
```
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvdf 202:80 0 30G 0 disk
xvda1 202:1 0 8G 0 disk /
```
Here you can see that the new volume, `/dev/xvdf`, is attached, but not mounted (because there is no path listed under the `MOUNTPOINT` column).
1. Use the **dd** or **fio** utilities to read all of the blocks on the device. The **dd** command is installed by default on Linux systems, but **fio** is considerably faster because it allows multi-threaded reads.
**Note**
This step may take several minutes up to several hours, depending on your EC2 instance bandwidth, the IOPS provisioned for the volume, and the size of the volume.
[**dd**] The `if` (input file) parameter should be set to the drive you wish to initialize. The `of` (output file) parameter should be set to the Linux null virtual device, `/dev/null`. The `bs` parameter sets the block size of the read operation; for optimal performance, this should be set to 1 MB.
**Important**
Incorrect use of **dd** can easily destroy a volume's data. Be sure to follow precisely the example command below. Only the `if=/dev/xvdf` parameter will vary depending on the name of the device you are reading.
```
$ sudo dd if=/dev/xvdf of=/dev/null bs=1M
```
[**fio**] If you have **fio** installed on your system, use the following command to initialize your volume. The `--filename` (input file) parameter should be set to the drive you wish to initialize.
```
$ sudo fio --filename=/dev/xvdf --rw=read --bs=1M --iodepth=32 --ioengine=libaio --direct=1 --name=volume-initialize
```
To install **fio** on Amazon Linux, use the following command:
```
sudo yum install -y fio
```
To install **fio** on Ubuntu, use the following command:
```
sudo apt-get install -y fio
```
When the operation is finished, you will see a report of the read operation. Your volume is now ready for use. For more information, see [Make an Amazon EBS volume available for use](ebs-using-volumes.md).
### Windows instances
Before using either tool, gather information about the disks on your system as follows:
**To gather information about the system disks**
1. Use the **wmic** command to list the available disks on your system:
```
wmic diskdrive get size,deviceid
```
The following is example output:
```
DeviceID Size
\\.\PHYSICALDRIVE2 80517265920
\\.\PHYSICALDRIVE1 80517265920
\\.\PHYSICALDRIVE0 128849011200
\\.\PHYSICALDRIVE3 107372805120
```
1. Identify the disk to initialize using **dd** or **fio**. The `C:` drive is on `\\.\PHYSICALDRIVE0`. You can use the `diskmgmt.msc` utility to compare drive letters to disk drive numbers if you are not sure which drive number to use.
------
#### [ Use the dd utility ]
Complete the following procedures to install and use **dd** to initialize a volume.
**Important considerations**
+ Initializing a volume takes from several minutes up to several hours, depending on your EC2 instance bandwidth, the IOPS provisioned for the volume, and the size of the volume.
+ Incorrect use of **dd** can easily destroy a volume's data. Be sure to follow this procedure precisely.
**To install dd for Windows**
The **dd** for Windows program provides a similar experience to the **dd** program that is commonly available for Linux and Unix systems, and it enables you to initialize Amazon EBS volumes that have been created from snapshots. The most recent beta versions support the `/dev/null` virtual device. If you install an earlier version, you can use the `nul` virtual device instead. Full documentation is available at [http://www.chrysocome.net/dd](http://www.chrysocome.net/dd).
1. Download the most recent binary version of **dd** for Windows from [http://www.chrysocome.net/dd](http://www.chrysocome.net/dd).
1. (Optional) Create a folder for command line utilities that is easy to locate and remember, such as `C:\bin`. If you already have a designated folder for command line utilities, you can use that folder instead in the following step.
1. Unzip the binary package and copy the `dd.exe` file to your command line utilities folder (for example, `C:\bin`).
1. Add the command line utilities folder to your Path environment variable so you can run the programs in that folder from anywhere.
1. Choose **Start**, open the context (right-click) menu for **Computer**, and then choose **Properties**.
1. Choose **Advanced system settings**, **Environment Variables**.
1. For **System Variables**, select the variable **Path** and choose **Edit**.
1. For **Variable value**, append a semicolon and the location of your command line utility folder (**;C:\$1bin\$1)** to the end of the existing value.
1. Choose **OK** to close the **Edit System Variable ** window.
1. Open a new command prompt window. The previous step doesn't update the environment variables in your current command prompt windows. The command prompt windows that you open now that you completed the previous step are updated.
**To initialize a volume using dd for Windows**
Run the following command to read all blocks on the specified device (and send the output to the `/dev/null` virtual device). This command safely initializes your existing data.
```
dd if=\\.\PHYSICALDRIVEn of=/dev/null bs=1M --progress --size
```
You might get an error if **dd** attempts to read beyond the end of the volume. You can safely ignore this error.
If you used an earlier version of the **dd** command, it does not support the `/dev/null` device. Instead, you can use the `nul` device as follows.
```
dd if=\\.\PHYSICALDRIVEn of=nul bs=1M --progress --size
```
------
#### [ Use the fio utility ]
Complete the following procedures to install and use **fio** to initialize a volume.
**To install **fio** for Windows**
The **fio** for Windows program provides a similar experience to the **fio** program that is commonly available for Linux and Unix systems, and it allows you to initialize Amazon EBS volumes created from snapshots. For more information, see [https://github.com/axboe/fio](https://github.com/axboe/fio).
1. Download the [**fio** MSI](https://github.com/axboe/fio/releases) installer by expanding **Assets** for the latest release and selecting the MSI installer.
1. Install **fio**.
**To initialize a volume using **fio** for Windows**
1. Run a command similar to the following to initialize a volume:
```
fio --filename=\\.\PHYSICALDRIVEn --rw=read --bs=1M --iodepth=32 --direct=1 --name=volume-initialize
```
1. When the operation completes, you are ready to use your new volume. For more information, see [Make an Amazon EBS volume available for use](ebs-using-volumes.md).
------
# Monitor the status of Amazon EBS volume initialization
When you create a volume, either from a snapshot or from another volume (volume copy), you can monitor the status of the volume initialization to determine whether the initialization process is complete. You can monitor volume initialization using the following options:
**Topics**
+ [
## AWS CLI and Amazon EC2 console
](#ebs-initialize-monitor-ec2)
+ [
## Amazon EventBridge
](#ebs-initialize-monitor-ev)
## AWS CLI and Amazon EC2 console
You can use the AWS CLI and Amazon EC2 console to check the status of the volume initialization at any time after the volume has been created. The following information is provided:
+ **Initialization type** (AWS CLI only) — Indicates the type of volume initialization used. `default` for fast snapshot restore and default volume initialization, `provisioned-rate` for Amazon EBS Provisioned Rate for Volume Initialization, and `volume-copy` for volume copy initialization.
+ **Estimated time to completion** (AWS CLI only) — Only for volumes created using a Amazon EBS Provisioned Rate for Volume Initialization. The estimated remaining time, in seconds, for the volume initialization to complete.
+ **Progress** — The progress, as a percentage (0-100), for the volume initialization process. For volumes initialized with fast snapshot restore, the progress moves to 100 percent immediately after creation.
+ **Initialization state** — The overall state of the volume initialization (`initializing` or `completed`). For volumes initialized with fast snapshot restore, the state moves to `completed` immediately after creation.
**Note**
It can take up to 5 minutes for the volume initialization information to be updated.
------
#### [ Console ]
**To monitor status of volume initialization**
1. Open the Amazon EC2 console at [https://console.aws.amazon.com/ec2/](https://console.aws.amazon.com/ec2/).
1. In the navigation pane, choose **Volumes**.
1. Select the volume for which to check the volume initialization status.
1. The **Initialization state** field in the grid and **Details** tab provide progress information in the following format: *Initialization state (progress percentage)*. For example, *Initializing (75%)*.
The possible initialization states include: *Initializing* and *Completed*.
------
#### [ AWS CLI ]
**To monitor status of volume initialization**
Use the [ describe-volume-status](https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-volume-status.html) AWS CLI command to view the initialization status. `EstimatedTimeToCompleteInSeconds` is returned only for volumes created with an Amazon EBS Provisioned Rate for Volume Initialization.
For example, the following command checks the initialization status for volume `vol-11111111111111111`, which was created with an Amazon EBS Provisioned Rate for Volume Initialization.
```
aws ec2 describe-volume-status --volume-id vol-01111111111111111
```
The following is example output.
```
{
"VolumeStatuses": [
{
"Actions": [],
"AvailabilityZone": "us-east-1a",
"Events": [],
"VolumeID": "vol-11111111111111111",
"VolumeStatus": {
"Details": [
{
"Name": "io-enabled",
"Status": "passed"
},
{
"Name": "io-performance",
"Status": "not-applicable"
},
{
"Name": "initialization-state",
"Status": "completed"
}
],
"Status": "ok"
},
"InitializationStatusDetails": {
"InitializationType": "provisioned-rate",
"Progress": 75,
"EstimatedTimeToCompleteInSeconds": 850
}
}
]
}
```
------
## Amazon EventBridge
An Amazon EventBridge event is sent to your account within five minutes **after** the volume initialization has completed. You can create rules that trigger programmatic actions in response to these events.
**Note**
Events are emitted on a best effort basis.
If you delete the volume before initialization completes, or within 5 minutes after initialization completes, you might not receive the event.
For more information about the event, see [EBS volume initialization event](ebs-cloud-watch-events.md#volume-initialization-events).
**To monitor status of volume initialization using EventBridge**
1. Open the Amazon EventBridge console at [https://console.aws.amazon.com/events/](https://console.aws.amazon.com/events/).
1. Choose **Rules**, **Create rule**.
1. For **Step 1**, do the following:
1. Specify a name and description for the rule.
1. For **Event bus**, choose the bus to receive the events. If you haven't created a custom event bus, keep **default**, or see [Creating an event bus](https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-create-event-bus.html).
1. For **Rule type**, keep **Rule with an event pattern**.
1. Choose **Next**.
1. For **Step 2**, do the following:
1. For **Event source**, keep **AWS events or EventBridge partner events**.
1. For **Creation method**, choose **Custom pattern (JSON editor)**.
1. For **Event pattern**, add the following:
```
{
"detail-type": ["EBS Volume Notification"],
"source": ["aws.ec2"],
"detail": {
"event": ["initializeVolume"],
"result": ["succeeded"]
}
}
```
For an example event, see [EBS volume initialization event](ebs-cloud-watch-events.md#volume-initialization-events).
1. Choose **Next**.
1. For **Step 3**, do the following:
1. For **Target types**, choose **AWS service**.
1. For **Select target**, choose **SNS topic**, and for **Topic** select the required topic. If you haven't created any topics, see [Creating a topic](https://docs.aws.amazon.com/sns/latest/dg/sns-create-topic.html).
1. For **Permissions**, keep **Use execution role (recommended)** selected.
1. For **Execution role**, keep **Create a new role for this specific resource** selected and the defauly role name.
1. Choose **Next**.
1. For **Step 4**, specify tags for the rule if needed, and then choose **Next**.
1. For **Step 5**, review the rule and then choose **Create rule**.