What is a volume?
A volume is a file storage which is similar to SSD and HDD hard disks but located in the cloud.
Gcore Cloud uses a software-defined distributed file system for data storage, which is an easily scalable node cluster. System nodes provide storage and triple data replication, as well as load distribution, which guarantees high availability of volumes.
Use volumes for information storage and data management when connecting to an instance.
Use these links for better navigation:
- Create an image from the bootvolume
- Take snapshot
- Revert volume to the latest snapshot
The Volume section displays both disks that were added and those that were not added to instances in the selected location, their name in the system, and the creation date.
If a disk is attached to an instance, in the Instance column will be indicated to which machine this volume is added.
To learn more about an Instance, click on its name.
If a volume is not attached to an instance, in the Instance column the "Attach to instance" will be displayed.
To attach a volume to an instance, click "Attach to instance", in the pop-up window select the instance you need and click Attach volume.
How to create a volume?
You can create volumes while creating an instance and in the Volume section.
To create a volume in the Volume section:
1. Go to the Volume section and click Create volume.
A dialog box will be opened.
2. Specify the required volume size in GB.
3. Depending on the data, select the volume type: faster for critical data and slower for archived data.
Four types of volumes are available:
- High IOPS SSD — (High IOPS network SSD disk) - The Highest performance network SSD block storage designed for latency-sensitive transactional workloads (60 IOPS per 1 GB; 2.5 MB/s per 1 GB). The IOPS performance limit is 9000. The bandwidth limit is 500 MB/s.
- Standard (Standard network SSD disk) - High-performance network SSD block storage with stable and high random IO performance, and high data reliability (6 IOPS per 1 GB; 0.4 MB/s per 1 GB). The IOPS performance limit is 4500. The bandwidth limit is 300 MB/s.
- Cold (Network HDD disk) - The Lowest cost HDD block storage for less frequently accessed workloads (maximum 500 IOPS and 100 MB/s.). The IOPS performance limit is 1000. The bandwidth limit is 100 MB/s. For Cold Volumes, we cannot guarantee these values permanently.
- Ultra - Network Block Storage. Can be used for non-critical data and less frequently accessed workloads. The IOPS performance limit is 1000. The bandwidth limit is 100 MB/s.
For the High IOPS SSD and Standard volume types, the following functions are supported:
- Volume IO Burst
- Volume Throughput Burst
The options provide IO credits and throughput credits. Credits apply when the volume type base limits are exceeded, it ensures optimal volume performance at peak IOPS and throughput.
Credits increase IOPS and volume throughput in 10 times and allow volumes to continuously run at this speed (x10) for 10 minutes.
For example, a 3 GB High IOPS SSD volume is attached to your instance.
The base limits of such the volume are: 60 IOPS x 3 GB + 2.5 MB/s x 3 GB = 180 IOPS +7.5 MB.
If IOPS and throughput values exceed these parameters, the following renewable resources will be added: (60 IOPS x 3 GB + 2.5 MB/s x 3 GB = 180 IOPS + 7.5 MB) x 10 = 1800 IOPS + 75 MB/s.
After the peak values and reducing the load to the base level, credits are restored. The more the load decreased after the peak, the faster the credits will recover. If the base limits are exceeded again, renewed credits will be applied.
4. To attach the volume to an instance, select it from the pop-up list.
! If you don't want to attach the volume to an instance, skip this field.
5. Enter the name and click Save.
You will see the created volume in the Volume section.
The volume can be created only in the location indicated in the upper-right corner.
Please, note! From our side, the volumes are issued in order, but we can't guarantee consistency in the names of volumes in the OS (sda, sdb, sdc ...) while adding Volumes, via UI/API
The sequence of the Volume names is determined on the OS side.
When working with Volumes in the OS, it is better to pay attention to the UUID.
Actions with volumes
You can detach the created volume from the instance, change its size, type, make a snapshot, or delete it by clicking on the three-dot icon next to the necessary volume. Also, you can create an image from the boot volumes.
Select the necessary action in the menu.
1. Create an image (from the bootvolume)
Enter a name for the image and click on "Create image" button. Within several minutes, the image will be created and available in the "Images" section.
2. To detach a volume from an instance:
Select the instance from which you want to detach the selected volume. Click OK to detach the volume.
Attention! Detaching a volume will not cancel your payment for it. You can attach a volume to any instance at any time.
3. Resize volume:
The opened window shows the current volume size. Use keyboard input or arrows to set the new volume size. Click Resize volume to save your settings.
4. Retype volume:
Detach a volume from an instance. Select the necessary volume type. Click Retype to save the settings.
Important! Volume conversion is only possible for High IOPS and Standard. Conversion to and from the Cold type is not possible.
Also, you can migrate data between disks within an OS using "rsync" or "cp" utilities.
5. Take snapshot:
To take a snapshot, enter its Name and click Take snapshot.
6. Delete volume:
You can only delete volume that is not attached to an instance.
To delete a volume that is attached to an instance, firstly click Detach in the menu. Then delete the volume, by clicking on the Delete in the menu.
Important! The instance boot volume can only be deleted together with the instance in the instance management section.
7. Revert volume to the latest snapshot
Detach the volume from your instance and then revert it to the latest snapshot by clicking on the desired option on the selector.
Please note: if you have just resized the volume you will not be able to use the function because the last snapshot is designed for the old size. You can only create a new volume from it. For the new size volume, you need to create a new snapshot.