Persistent Disks

 

• Are durable network storage devices that you can provision to host your virtual machine instances.

Features

• Data on each persistent disk is distributed across several physical disks and is designed for high durability. It stores data redundantly to ensure data integrity.
• Persistent disks are resizable to accommodate larger storage requirements.
• It can be attached to virtual machines running on Compute Engine (GCE) or Google Kubernetes Engine (GKE).
• You cannot attach a persistent disk to an instance on another project.
• Your storage is independent of your virtual machine instances so you can detach or move your PDs to keep your data even after you delete your instances.
• You can only change the size of a Persistent Disk incrementally.

Zonal and Regional Persistent Disks

You can configure your PD to be zonal or regional.

• Zonal Disks
  • Are relatively faster than Regional disks and are found in a zone.
• Regional Disks
  • Provides replication of data between two zones in the same region.
  • Is designed for building robust and highly available systems on Compute Engine.

Persistent Disk Types

• Standard (pd-standard)
  • Backed by standard hard disk drives (HDD).
  • Efficient and economical for handing sequential read/write operations but they aren’t optimized to handle high rates of random input/output per second (IOPS).
• Balanced and SSD Disks
  • Backed by solid state drives (SSD)
  • SSD persistent disks are designed for single-digit millisecond latencies

Encryption

• Data on persistent disks are automatically encrypted at rest and in transit by system defined encryption keys or with customer-supplied keys.
• To control your data encryption, you can create PDs with your own encryption keys.

Snapshots

• Persistent disk snapshots can be created to protect against data loss.
• Snapshots are incremental and take only minutes to create even if you snapshot disks that are attached to running instances.
• You can set up a snapshot schedule to back up your data on a regular basis.

Pricing

• Provisioning persistent disks incurs cost based on the following factors:
  • Amount and location of provisioned space per disk
  • Snapshot Storage
  • Network charges for snapshot creation