network volumes
network volumes are scalable block devices that can be easily migrated between cloud servers. Suitable for scaling server disk space without changing the boot disk. Triple replication of disk volumes ensures high data integrity.
A network volume can be created with the cloud server or created separately, and then create a server from it or connect it to the server as an additional disk.
Features of network drives
- There are four types of network volumes available — with different bandwidths, IOPS limits, and recommended size limits.
- You can use it as a cloud server boot (system) disk or mount as an additional disk.
- You can connect up to 255 network volumes to a single cloud server if you use a standard virtio-scsi property disk (up to 4 when using ide, up to 26 when using virtio-blk).
- The network volume can be disconnected from the server.
- You can enlarge the network volume.
- From a network drive, you can create an image, snapshot or another disk, set up backups.
- You can transfer disk between pool segments, projects, and accounts.
Types of network drives
- Basic HDD — HDD disk based on enterprise-class SATA disks. Suitable for storing large amounts of data that does not need to be read or rewritten frequently;
- Basic SSD — SSD disk for tasks where high read and write speeds are not required. Throughput and IOPS are higher than the base HDD;
- Universal SSD — SSD disk, suitable for use as a cloud server boot disk;
- Fast SSD — NVMe SSD disk with lower response time and faster performance than other types. Suitable for workloads that require high read and write speeds.
Network disk limits
The maximum size of boot and additional network volumes, throughput values, and read/write IOPS limits depend on the disk type.
Disks of the same type in different pool segments can have different limits. If two network volumes with SSD Universal type are in different segments (the first disk in ru-1c, the second in ru-8a), their limits will be different.
You can view the availability of network volumes in regions in the Cloud Platform network volumes availability matrix.
You can test disk performance.
What affects performance
Different types of disks have different IOPS values — the number of read and write operations per second. File system creation and verification are procedures that require a certain number of read and write operations to be performed on a disk. The better the performance of the disk, the faster these operations are completed.
When the cloud server is first started, the file system on the system disk is "stretched" to fit the size of the disk. The larger the disk size and the lower its IOPS limits, the longer this process will take — hence, the longer the cloud server will take to start up.
The size of the file system affects the time it takes to check its state in the event of a server crash. Validation is enabled by default for boot (system) disks of all servers that are created from ready-made images.
Cost
network volumes are paid using cloud platform payment model.
The cost depends on the type of disk, size, and pool segment in which it is located.
Every GB of network volumes is paid for. The cost per GB can be viewed at selectel.ru.