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Google Compute Engine

Disks

Google Compute Engine offers several types of data disk that can be used as primary storage for your virtual machine instances:

  • Persistent disk storage, available as both standard (HDD) and solid-state (SSD), exists independently of your virtual machine instances. A persistent disk can be attached and detached to any instance in the same zone. Data stored in persistent disk storage remains intact regardless of the state of the instance to which it is attached.
  • Local SSD storage is physically attached to the server running a given virtual machine instance. In contrast to persistent disk storage, data stored on local SSD does not persist beyond the lifetime of the instance to which the local SSD is attached.

Contents

Overview of disk types

Standard persistent disks (HDD)

Standard persistent disks have the following attributes:

  • Efficient and economical when handling sequential input/output operations
  • Flexible partition sizing
  • Redundant, industry-standard data protection
  • Snapshotting capabilities
  • Can be attached to any machine type
  • Can be used as a boot disk for a virtual machine instance

Use standard persistent disks when your limiting factor is space or streaming throughput.

Solid-state persistent disks (SSD)

Solid-state persistent disks have the following attributes:

  • Efficient and economical when handling high rates of random input/output operations per second (IOPS)
  • Low latency
  • Flexible partition sizing
  • Redundant, industry-standard data protection
  • Snapshotting capabilities
  • Can be attached to any machine type
  • Can be used as a boot disk for a virtual machine instance

Use solid-state persistent disks when your limiting factor is random IOPS or streaming throughput with low latency.

Local SSDs

Local SSDs have the following attributes:

  • Extremely efficient when handling high rates of random input/output operations per second (IOPS)
  • Most economical option per GB and per MB/s of throughput
  • Extremely low latency
  • Ephemeral, as they are tied to the life of the virtual machine instance on which they are mounted
  • Fixed partition size
  • Can be attached to any machine type

Use local SSDs for use cases where you need a fast scratch disk or cache and don't want to use pure RAM, or when your workload itself is replicated across instances.

Comparison of disk types

Standard persistent disks SSD persistent disks Local SSD (SCSI) Local SSD (NVMe)
General
Data redundancy Yes Yes No No
Disk interface Virtio SCSI Virtio SCSI Virtio SCSI NVMe
Encryption Yes Yes Yes Yes
Snapshotting Yes Yes No No
Zone availability All zones All zones Most zones Most zones
Maximum sustained IOPS
Read IOPS per GB 0.3 30 266.7 453.3
Write IOPS per GB 1.5 30 186.7 240
Read IOPS per instance 3000 10,000 400,000 680,000
Write IOPS per instance 15,000 15,000 280,000 360,000
Maximum sustained throughput (MB/s)
Read throughput per GB 0.12 0.48 1.04 1.77
Write throughput per GB 0.09 0.48 0.73 0.94
Read throughput per instance 180 240 1,560 2,650
Write throughput per instance 120 240 1,090 1,400