To protect your applications from a zonal outage, use Hyperdisk Balanced High Availability volumes to synchronouslyreplicate data across two zones in the same region. You can also use Hyperdisk Balanced High Availabilityvolumes in scenarios that require write access to the same volume multiple zones.This document describes the features of Hyperdisk Balanced High Availability.

You can specify up to 100,000IOPS and 1,200 MiB/s of throughput for a single Hyperdisk Balanced High Availability volume.Hyperdisk Balanced and Hyperdisk Balanced High Availability are the only Hyperdisk types you can use as a boot disk.

To create a new Hyperdisk Balanced High Availability volume, seeCreate and manage regional disks.

For more information about Hyperdisk and the otherHyperdisk types, seeAbout Hyperdisk.

Machine series support

You can use Hyperdisk Balanced High Availability with the following machine series:

• C4
• C4A
• C3
• C3D
• N4
• N4A (Preview)
• N4D
• Z3
• M3
• A3 (H200)
• A3 (H100)
• G4

Use cases

Use Hyperdisk Balanced High Availability for any application that requires high availability andresilience to zonal outages, such as the following:

• High performance workloads that require fast failover
• Workloads that require concurrent write access to data from instances thatare in different zones
• Workloads with regulatory requirements for data replication in two locations
• Microsoft SQL Server Failover Cluster Instances (FCI)

Disaster protection for Hyperdisk Balanced High Availability volumes

You can back up a Hyperdisk Balanced High Availability volume withinstant snapshotsandstandard snapshots.Snapshots back up the data on a Hyperdisk Balanced High Availability volume at a specific point in time.

To protect your data in the unlikely event of an outage, you can enablereplication across multiple zones and multiple regions for Hyperdisk Balanced High Availability volumes.

Synchronous replication across multiple zones

Zonal replication, also referred to as synchronous replication,of a Hyperdisk Balanced High Availability volume creates replicas of the volume's data intwo zones. If there's a temporary outage in one zone, the replica in the other zoneensures the data is still available.To learn more about zonal replication, seeAbout synchronous replication.

Asynchronous replication across multiple regions

You can protect your data in the unlikely event of a regional outage by enabling Asynchronous Replication. Asynchronous Replication maintains a copy ofthe data on your volume in another region. For example, to protect aHyperdisk Balanced High Availability volume inus-west1,you can use Asynchronous Replication to replicate the volume to a secondary volume intheus-east4 region. If the volume inus-west1became unavailable, then you could use the secondary volume inus-east4.

About provisioned performance for Hyperdisk Balanced High Availability

You don't have to provision performance when you createHyperdisk volumes. If you don't provision performance, Compute Enginecreates the volume with default values that you can modify later.For details about default values, seeDefault IOPS andthroughput values.

If you know your performance needs, you can specify IOPS and throughput limitsfor a Hyperdisk Balanced High Availability volume when you create the volume, and you can changethe provisioned values after the volume has been created. You can't specify anIOPS or throughput level if you don't specify a size.

Important: Hyperdisk volumescan't reach the provisioned performance unless the compute instance supports thatlevel of performance. For detailed performance limits for all supported instancesby machine type, seePerformance limits when attached toan instance.

Size and performance limits

The following limits apply to the size, IOPS, and throughput values you can specifyfor a Hyperdisk Balanced High Availability volume.

• Size: between 4 GiB and 64 TiB.The default size is 100 GiB.
• IOPS: between 3,000 and 100,000 IOPS.For volumes less than 320 GiB, the range of IOPS values you can specify varies by size.For details, seeLimits for configurable IOPS.
• Throughput: between 140 and 1,200 MiB/sof throughput, but the throughput value depends on how much IOPS you provision.For details, seeLimits for provisioned throughput.

Limits for configurable IOPS

You can choose the IOPS limit for a Hyperdisk Balanced High Availability volume according to the followinglimits. The minimum and maximum limits vary by size, as follows

• Minimum configurable IOPS:
  • 4 or 5 GiB volumes: IOPS is fixed at 2,000 and 2,500 IOPS, respectively.
  • 6 GiB-64 TiB: at least 3,000 IOPS.
• Maximum configurable IOPS:
  • 6-200 GiB volumes: varies according to this formula, wherex is the volume's size in GiB:MIN (500x or 100,000).
  • 201 GiB-64 TiB volumes: at most 100,000 IOPS.

The following table lists the limits for configurable IOPS for common volume sizes.If a size isn't listed, use the previously mentioned formula to calculate themaximum configurable IOPS.

Size (GiB)	Configurable IOPS values
4	2,000
5	2,500
10	3,000-5,000
50	3,000-25,000
150	3,000-75,000
200 or more	3,000-100,000

Limits for configurable throughput

Volumes with 4-5 GiB of capacity have a fixed throughput value of140 MiB/s.For larger volumes, you can provision additional throughput. The range of supportedthroughput values depends on the provisioned IOPS, based on the following formulas.P is the provisioned IOPS value.

• Minimum configurable throughput:MAX (140, P/256) MiB/s
• Maximum configurable throughput:MIN (1200 MiB/s, P/4) MiB/s

The following table lists the limits for some provisioned IOPS values and thecorresponding throughput ranges. If a size isn't listed, use the formula tocalculate the allowable values.

Provisioned IOPS	Configurable throughput (MiB/s)
2,000	140-500
2,500	140-625
3,000	140-750
4,000	140-1,000
8,000	140-1,200
32,000	140-1,200
50,000	156-1,200
64,000	250-1,200
3,000-100,000	140-1,200
3,000-100,000	250-1,200

Default size, IOPS, and throughput values

If you don't specify a size, IOPS, or throughput value when you create a Hyperdisk Balanced High Availabilityvolume, Compute Engine assigns default values.

The default size is 100 GiB.

The default IOPS and throughput are based on the following formulas, wherexis the volume's size in GiB.

• Default IOPS:
  • Volumes 6 GiB or less:500x IOPS
  • Volumes 6 GiB and 26.666667 TiB:6x + 3,000 IOPS
  • Volumes larger than 26.666667 TiB: 100,000 IOPS
• Default throughput
  • Volumes 6 GiB or less:140 MiB/s
  • Volumes larger than 6 GiB:1.5x + 140 MiB/s

Change the provisioned performance or size

You can change the provisioned performance and size of a Hyperdisk Balanced High Availability volume atmost once every 4 hours.To learn how to modify size or performance, seeModify a Hyperdisk volume.

Baseline performance

Hyperdisk Balanced High Availability volumes include baseline, or free performance. The first 3,000 IOPS and140 MiB/s of throughput that you provision for a volume are free.Performance you provisionabove the baseline amounts isbillable performance,and is not free. If you provision a volume with 5,000 IOPS, you're billed for2,000 IOPS. Similar principles apply to throughput.

Baseline performance and quota

Baseline IOPS and throughput don't affect the IOPS and throughput quota for aproject's Hyperdisk Balanced and Hyperdisk Balanced High Availability volumes.

For example, if your project has a quota of 500,000 IOPS and you create a Hyperdisk Balancedvolume with 3,000 IOPS, then you still have a quota of 500,000 IOPSafter you create the volume. If you also create a Hyperdisk Balanced High Availability volume with 4,000 IOPS,then the project would have a remaining IOPS quota of 499,000.

Limits for consuming baseline performance

A project's Hyperdisk Balanced and Hyperdisk Balanced High Availability volumesthat are in the same zone can concurrently use up to 50 GiB/sof baseline throughput and up to 500,000 of baseline IOPS.This limit is referred to as theconcurrent consumption limit for baseline performance.

The concurrent consumption limit for baseline performance restricts how much baseline performance thevolumes canuse at the same time, and doesn't affect much baseline performanceyou can provision. The concurrent consumption limit doesn't apply to consuming orprovisioning billable performance.

For more information, seeConcurrent consumption limits for baseline performance.

Performance limits when attached to an instance

This section lists the performance limits for Hyperdisk Balanced High Availability.You can specify up to 100,000IOPS and 1,200 MiB/s of throughput for a single Hyperdisk Balanced High Availability volume.

This section lists the maximum performance that Hyperdisk Balanced High Availability volumescan achieve for each supported instance. A Hyperdisk Balanced High Availability volume's performancewhen it's attached to an instance can't exceed the limits for the instance'smachine type.The performance limits are also shared across all Hyperdisk Balanced High Availability volumesattached to the same instance, regardless of each volume's provisioned performance.

Achieve higher performance with multiple Hyperdisk Balanced High Availability volumes

Certain instances can exceed the maximum performance for a single Hyperdisk Balanced High Availability volume—100,000 IOPS or 1,200 MiB/s. An instance can achieve thesehigher limits if you attach multiple Hyperdisk Balanced High Availability volumes to the instance.

If an instance's performance limit in the following table exceeds100,000 IOPS or 1,200 MiB/s, then the instance can achieve thatlimit only if you attach multiple Hyperdisk Balanced High Availability volumes.For example, the performance limit for ac4a-*-72 instance using Hyperdisk Balanced High Availabilityis 240,000 IOPS and 5,000 MiB/s. To achieve this maximum performanceyou must attach at least five Hyperdisk Balanced High Availability volumes to the instance.

Important: To reach the IOPS limits, you must use an I/O size of4 KB. Maximum throughput limits require an I/O size of at least256 KB.
Hyperdisk performance is half-duplex,so the IOPS and throughput limits are shared between read and write operations.This means that if a machine type has a 50,000 IOPS limit, then the sum of the readsand writes every second can't exceed 50,000.

Regional availability for Hyperdisk Balanced High Availability

Hyperdisk Balanced High Availability is available in all regions.

Share a Hyperdisk Balanced High Availability volume between VMs

To enable workload clustering and rapid high-availability (HA) failover with arecovery time objectiveof less than one second, you can attach the same Hyperdisk Balanced High Availability volume to multipleinstances. When you attach a Hyperdisk Balanced High Availability volume to multiple instances at the sametime, each instance maintains write access to the volume. To attach a volume tomultiple instances, each instance must be in the same zone as the volume's replicas.

To learn more, seeShare a disk between VMs.

Pricing

You're billed for the total provisioned size, IOPS, and throughput of your Hyperdisk Balanced High Availabilityvolumes until you delete them. Charges incur even if the volume isn't attached to anyinstances or if the instance is suspended or stopped. For more information,seeDisk pricing.

Limitations for Hyperdisk Balanced High Availability

• You can't create amachine image from aHyperdisk Balanced High Availability volume.
• Hyperdisk Balanced High Availability volumes in multi-writer mode have additionallimitations.
• You can change a Hyperdisk volume's size and performance everyat most once every 4 hours.
• Compute Engine enforces a concurrent consumption limit for baseline performance for a project's Hyperdisk Balancedand Hyperdisk Balanced High Availability volumes that are in the same zone. The limits are 500,000 IOPS and 50 GiB/s ofthroughput. For more information, seeConcurrent consumption limits for baseline performance.

What's next

• Add a Hyperdisk volume to your VM