Skip to main content

Service overview

Virtual Disk Service is a pay-as-you-go, flexible and convenient way to expand storage for Virtual Compute Service (VCS) instances. It is designed as the storage space for TWSC VCS service to provide high-availability, consistent, and low-latency services.


Virtual Disk Service (VDS) plays a significant role in Virtual Compute Service (VCS):


VCS instance storage

  • System disks
    We provide a system disk with 5 options: 100 GB - 500 GB (HDD) in a VCS instance.
  • Data disks
    VCS instances can mount multiple data disks to expand the storage. VDS provides the following two disk types:
    • Solid-state drive (SSD):
    • Solid-state drive (SSD):
      • Provides low-latency services (less than 10 milliseconds), efficient and stable transfers (from 3 IOPS/GB to 16 IOPS/GB) to enhance the reliability and scalability of applications. SSD is well-suited for enterprise applications that require high performance and high-throughput computations with big data.
      • Provides a maximum transfer capability of 2,375 MB/sec for each VCS instance.
      • Supports up to 16 TB of storage space.
    • Hard disk drive (HDD):
      • Provides transfer capability of 250 MB/sec per TB. HDD is well-suited for mass data that is not frequently accessed and is unaffected by delays.
      • Provides a maximum transfer capability of 2,375 MB/sec for each VCS instance.
      • Supports up to 16 TB of storage space.

Instances and disks backup service

TWSC provides storage for the backup of images and data disks of VCS instances.


Virtual Disk Lifecycle

  • System disks
    System disks are configured together when the VCS instances are created, and cannot be separated from them. When an instance is deleted, the system disk attached to it will also be deleted, and the billing will stop.
  • Data disks
    • Data disks can be created in advance and attached to a VCS instance after the instance is created, or they can be created simultaneously with the VCS instance and automatically attached to it.
    • Data disks can be detached from instances. Data disks attached to VCS instances are displayed as "IN-USE" on the Data Disk Management page. Data disks that are not attached to any VCS instances are displayed as "AVAILABLE".
    • Regardless of whether data disks are in "IN-USE" or "AVAILABLE" state, space is allocated and will be billed.
    • When a VCS instance is deleted, the data disk attached to it will only be detached from that instance and not deleted, and will continue to be billed.