U4 Ultra Low Latency (ULL) machine family

Private Preview — ULL Solution

This product or feature is subject to the "Pre-GA Offerings Terms" in the General Service Terms section of the Service Specific Terms. Pre-GA features are available "as is" and might have limited support. For more information, see the launch stage descriptions.

ULL Solution is available only to approved exchange operators and their exchange participants. If you are an approved exchange participant, contact [e-mail] to request access.

This document describes the U4 network-optimized machine family. U4 is Google Cloud's Ultra Low Latency (ULL) network-optimized machine family. U4 is designed to support the core workloads for financial exchange ecosystems by offering industry specific instance networking capabilities in the public cloud. The U4P and U4C machine series are based on Intel's 5th generation (code-named Emerald Rapids) Xeon scalable processor, while the U4S machine series is based on Intel's 6th generation (code-named Granite Rapids) Xeon scalable processor.

The U4 network-optimized machine family offers three machine series:

• U4P: Bare metal machine types with or without attached Titanium SSD disks
• U4C: Bare metal machine types with or without attached Titanium SSD disks
• U4S: Available in several different virtual machine (VM) type sizes, either with or without attached Titanium SSD disks

Each machine type within a machine series has a specific number of CPUs, memory, number of NUMA domains, and network bandwidth.

Recommended machine series by workload type

The following table provides the recommended machine series based on your workloads.

Note: U4P machines are available only to exchange operators.

Machine series	Used by	Workload type
U4P	Exchange operators (providers)	Trading systems
U4C	Exchange participants	Execute trading strategies
U4S	Exchange operators Exchange participants Service providers	Auxiliary workloads Exchange ecosystem services

While U4P and U4C instances support ULL unicast and multicast traffic, U4S instances provide support for non-ULL workloads with close physical proximity to U4P and U4C instances for reduced latency.

U4C machine series

The U4C machine series runs on Intel's 5th generation Xeon Scalable processor (code named Emerald Rapids) and is optimized for ultra low latency, financial exchange services. Only bare metal machine types are available, metal instances provide direct access to the underlying server CPU and memory with no virtualization or Compute Engine hypervisor in the middle. Each instance uses two sockets of the host machine, with 60 cores per socket. Each instance has 3 physical NICs.

Any advanced features available and enabled in the host CPU are available to the U4C bare metal instances, even if the Compute Engine instances don't expose those features.

Supported features

The U4C machine series has the following features:

• Powered by Intel's Emerald Rapids processor and Titanium.
• Offers 120 CPUs and 512 GB of memory.
• Supports up to 12 TiB of local Titanium SSD disks.
• Offers only predefined machine types.
• Supports standard network configuration with up to 100 Gbps bandwidth on NIC0, for communication within Google Cloud.
• Uses ULL VPC networks for communication with U4P instances.
• Can be used with Hyperdisk Balanced and Hyperdisk Extreme block storage.
• Supports compact and spread placement policies.
• Can be used with stateful or stateless managed instance groups.

U4C machine types

U4C machine types are available as predefined configurations:

• highcpu configurations have 120 CPUs and 512 GB of memory

To use Titanium SSD with U4C, create your instance using the lssd variant of the U4C machine types. Selecting this machine type creates an instance of the specified size with Titanium SSD partitions attached. You can't attach Titanium SSD volumes separately.

Machine type	vCPU count^1	Memory (GB)	Attached Titanium SSD(GiB)	Physical NIC count	Egress bandwidth (Gbps)^2
u4c-highcpu-120-lssd-metal	120	512	(4 x 3,000 GiB) 12,000 GiB	3	Up to 100 Gbps Up to 1 Gbps (ULL)

¹Bare metal instances don't use vCPUs. For bare metal instances, the number of vCPUs is equivalent to the number of hardware threads on the host server.
²Maximum egress bandwidth cannot exceed the number given. Actual egress bandwidth depends on the destination IP address and other factors. See Network bandwidth.

Supported disk types for U4C instances

U4C instances can use the following block storage types:

• Hyperdisk Balanced (hyperdisk-balanced)
• Hyperdisk Extreme (hyperdisk-extreme)
• Local Titanium SSD

Disk capacity limits for U4C instances

The limits for Google Cloud Hyperdisk with U4C instances are:

• Maximum number of Hyperdisk disks attached to an instance: 32
• Maximum disk capacity across all Hyperdisk disks for an instance: 512 TiB

For more information about disk capacity limits, see Hyperdisk capacity limits per VM.

Disk performance limits for U4C instances

The performance limits for Titanium SSD and Hyperdisk per instance are listed in the following tables:

Titanium SSD

Machine type	Number of Titanium SSD disks	Total storage space (GiB)	Read IOPS	Write IOPS	Read throughput (MiB/s)	Write throughput (MiB/s)
u4c-highcpu-120-lssd-metal	4	12,000	7,200,000	3,600,000	30,000	15,840

Hyperdisk

Disk type	Maximum disks per instance	Maximum IOPS	Maximum throughput (MiB/s)
Hyperdisk Balanced	32	275,000	8,750
Hyperdisk Extreme	8	380,000	8,750

For more information about performance limits, see the following:

• Hyperdisk limits per instance
• Performance limits by Hyperdisk type

Network support for U4C instances

U4C instances come with 3 physical NICs per instance.

Network interface	Driver	Usage	Internal egress bandwidth	External egress bandwidth
NIC0	AF-XDP supported Google Virtual NIC (gVNIC)	General instance communication within Google Cloud	Up to 100 Gbps	Up to 25 Gbps
NIC1 (ULL A)	AF-XDP supported Google Virtual NIC (gVNIC)	ULL unicast and multicast communication	Up to 1 Gbps	N/A
NIC2 (ULL B)	AF-XDP supported Google Virtual NIC (gVNIC)	ULL unicast and multicast communication	Up to 1 Gbps	N/A

The NUMA alignment for the ULL NICs is as follows: NIC1 (ULL A) uses NUMA node 0, while NIC2 (ULL B) uses NUMA node 2.

U4S machine series

The U4S machine series is a general-purpose machine series intended to run auxiliary workloads for U4C and U4P instances that don't require a direct connection to a ULL VPC network. U4S instances are powered by 6th generation (code-named Granite Rapids) Intel Xeon Scalable processors and Titanium.

Supported features

The U4S machine series has the following features:

• Powered by Intel's Granite Rapids processor and Titanium.
• Supports up to 18 TiB of local Titanium SSD disks.
• Offers only predefined machine types.
• Supports standard network configuration with up to 100 Gbps bandwidth.
• Can be used with Hyperdisk Balanced and Hyperdisk Extreme block storage.
• Supports compact and spread placement policies.

U4S machine types

U4S VMs are available as predefined configurations in sizes ranging from 2 vCPUs to 288 vCPUs and up to 2,232 GB of memory. The following preconfigured machine type names correspond to the amount of memory configured for the instance:

• highcpu: 2 GB memory per vCPU
• standard: 3.75 GB memory per vCPU
• highmem: 7.75 GB memory per vCPU

To use Titanium SSD with U4S, create your instance using the -lssd variant of the U4S machine types. Selecting this machine type creates an instance of the specified size with Titanium SSD partitions attached. You can't attach Titanium SSD volumes separately.

U4S standard

Machine type	vCPU count^1	Memory (GB)	Attached Titanium SSD(GiB)	Physical NIC count	Egress bandwidth (Gbps)^2,3	Tier_1 egress bandwidth^3
u4s-standard-2	2	7	No	1	Up to 10	N/A
u4s-standard-4	4	15	No	1	Up to 23	N/A
u4s-standard-8	8	30	No	1	Up to 23	N/A
u4s-standard-16	16	60	No	1	Up to 23	N/A
u4s-standard-24	24	90	No	1	Up to 23	N/A
u4s-standard-32	32	120	No	1	Up to 23	N/A
u4s-standard-48	48	180	No	1	Up to 34	Up to 50
u4s-standard-96	96	360	No	1	Up to 67	Up to 100
u4s-standard-144	144	540	No	1	Up to 100	Up to 150
u4s-standard-192	192	720	No	1	Up to 100	Up to 200
u4s-standard-288	288	1,080	No	1	Up to 100	Up to 200

¹ A CPU uses two threads per core, and a vCPU represents a single thread. See CPU platforms.
² Default egress bandwidth can't exceed the number given. Actual egress bandwidth depends on the destination IP address and other factors. See Network bandwidth.
³ Supports high-bandwidth networking for larger machine types.

U4S highcpu

Machine type	vCPU count^1	Memory (GB)	Attached Titanium SSD(GiB)	Physical NIC count	Egress bandwidth (Gbps)^2,3	Tier_1 egress bandwidth^3
u4s-highcpu-2	2	4	No	1	Up to 10	N/A
u4s-highcpu-4	4	8	No	1	Up to 23	N/A
u4s-highcpu-8	8	16	No	1	Up to 23	N/A
u4s-highcpu-16	16	32	No	1	Up to 23	N/A
u4s-highcpu-24	24	48	No	1	Up to 23	N/A
u4s-highcpu-32	32	64	No	1	Up to 23	N/A
u4s-highcpu-48	48	96	No	1	Up to 34	Up to 50
u4s-highcpu-96	96	192	No	1	Up to 67	Up to 100
u4s-highcpu-144	144	288	No	1	Up to 100	Up to 150
u4s-highcpu-192	192	384	No	1	Up to 100	Up to 200
u4s-highcpu-288	288	576	No	1	Up to 100	Up to 200

¹ A CPU uses two threads per core, and a vCPU represents a single thread. See CPU platforms.
² Default egress bandwidth can't exceed the number given. Actual egress bandwidth depends on the destination IP address and other factors. See Network bandwidth.
³ Supports high-bandwidth networking for larger machine types.

U4S highmem

Machine type	vCPU count^1	Memory (GB)	Attached Titanium SSD(GiB)	Physical NIC count	Egress bandwidth (Gbps)^2,3	Tier_1 egress bandwidth^3
u4s-highmem-2	2	15	No	1	Up to 10	N/A
u4s-highmem-4	4	31	No	1	Up to 23	N/A
u4s-highmem-8	8	62	No	1	Up to 23	N/A
u4s-highmem-16	16	124	No	1	Up to 23	N/A
u4s-highmem-24	24	186	No	1	Up to 23	N/A
u4s-highmem-32	32	248	No	1	Up to 23	N/A
u4s-highmem-48	48	372	No	1	Up to 34	Up to 50
u4s-highmem-96	96	744	No	1	Up to 67	Up to 100
u4s-highmem-144	144	1,116	No	1	Up to 100	Up to 150
u4s-highmem-192	192	1,488	No	1	Up to 100	Up to 200
u4s-highmem-288	288	2,232	No	1	Up to 100	Up to 200

¹ A CPU uses two threads per core, and a vCPU represents a single thread. See CPU platforms.
² Default egress bandwidth can't exceed the number given. Actual egress bandwidth depends on the destination IP address and other factors. See Network bandwidth.
³ Supports high-bandwidth networking for larger machine types.

U4S standard with Local SSD

Machine type	vCPU count^1	Memory (GB)	Attached Titanium SSD(GiB)	Physical NIC count	Egress bandwidth (Gbps)^2,3	Tier_1 egress bandwidth^3
u4s-standard-4-lssd	4	15	(1 x 375 GiB) 375 GiB	1	Up to 23	N/A
u4s-standard-8-lssd	8	30	(1 x 375 GiB) 375 GiB	1	Up to 23	N/A
u4s-standard-16-lssd	16	60	(2 x 375 GiB) 750 GiB	1	Up to 23	N/A
u4s-standard-24-lssd	24	90	(4 x 375 GiB) 1,500 GiB	1	Up to 23	N/A
u4s-standard-32-lssd	32	120	(5 x 375 GiB) 1,875 GiB	1	Up to 23	N/A
u4s-standard-48-lssd	48	180	(8 x 375 GiB) 3,000 GiB	1	Up to 34	N/A
u4s-standard-96-lssd	96	360	(16 x 375 GiB) 6,000 GiB	1	Up to 67	N/A
u4s-standard-144-lssd	144	540	(24 x 375 GiB) 9,000 GiB	1	Up to 100	N/A
u4s-standard-192-lssd	192	720	(32 x 375 GiB) 12,000 GiB	1	Up to 100	N/A
u4s-standard-288-lssd	288	1,080	(48 x 375 GiB) 18,000 GiB	1	Up to 100	Up to 200

¹ A CPU uses two threads per core, and a vCPU represents a single thread. See CPU platforms.
² Default egress bandwidth can't exceed the number given. Actual egress bandwidth depends on the destination IP address and other factors. See Network bandwidth.
³ Supports high-bandwidth networking for larger machine types.

U4S highmem with Local SSD

Machine type	vCPU count^1	Memory (GB)	Attached Titanium SSD(GiB)	Physical NIC count	Egress bandwidth (Gbps)^2,3	Tier_1 egress bandwidth^3
u4s-highmem-4-lssd	4	31	(1 x 375 GiB) 375 GiB	1	Up to 23	N/A
u4s-highmem-8-lssd	8	62	(1 x 375 GiB) 375 GiB	1	Up to 23	N/A
u4s-highmem-16-lssd	16	124	(2 x 375 GiB) 750 GiB	1	Up to 23	N/A
u4s-highmem-24-lssd	24	186	(4 x 375 GiB) 1,500 GiB	1	Up to 23	N/A
u4s-highmem-32-lssd	32	248	(5 x 375 GiB) 1,875 GiB	1	Up to 23	N/A
u4s-highmem-48-lssd	48	372	(8 x 375 GiB) 3,000 GiB	1	Up to 34	N/A
u4s-highmem-96-lssd	96	744	(16 x 375 GiB) 6,000 GiB	1	Up to 67	N/A
u4s-highmem-144-lssd	144	1,116	(24 x 375 GiB) 9,000 GiB	1	Up to 100	N/A
u4s-highmem-192-lssd	192	1,488	(32 x 375 GiB) 12,000 GiB	1	Up to 100	N/A
u4s-highmem-288-lssd	288	2,232	(48 x 375 GiB) 18,000 GiB	1	Up to 100	Up to 200

¹ A CPU uses two threads per core, and a vCPU represents a single thread. See CPU platforms.
² Default egress bandwidth can't exceed the number given. Actual egress bandwidth depends on the destination IP address and other factors. See Network bandwidth.
³ Supports high-bandwidth networking for larger machine types.

¹A vCPU is implemented as a single hardware hyperthread on one of the available CPU platforms. For bare metal instances (U4P and U4C machines), the number of vCPUs is equivalent to the number of hardware threads on the host server.
²Maximum egress bandwidth cannot exceed the number given. Actual egress bandwidth depends on the destination IP address and other factors. See Network bandwidth.

Supported disk types for U4S instances

U4S instances can use the following block storage types:

• Hyperdisk Balanced (hyperdisk-balanced)
• Hyperdisk Extreme (hyperdisk-extreme)
• Local Titanium SSD

Disk capacity limits for U4S instances

The maximum total disk capacity across all disks attached to an instance can't exceed 512 TiB.

For more information about the capacity limits, see Hyperdisk capacity limits per VM.

	Maximum number of disks
Machine types	Hyperdisk per VM	Hyperdisk Balanced	Hyperdisk Throughput	Hyperdisk ML	Hyperdisk Extreme
u4s-*-2	8	8	0	0	0
u4s-*-4 u4s-(standard,highmem)-4-lssd	16	16	0	0	0
u4s-*-8 u4s-(standard,highmem)-8-lssd	32	32	0	0	0
u4s-*-16 u4s-(standard,highmem)-16-lssd	32	32	0	0	0
u4s-*-24 u4s-(standard,highmem)-24-lssd	32	32	0	0	0
u4s-*-32 u4s-(standard,highmem)-32-lssd	64	64	0	0	0
u4s-*-48 u4s-(standard,highmem)-48-lssd	64	64	0	0	0
u4s-*-96 u4s-(standard,highmem)-96-lssd	128	128	0	0	8
u4s-*-144 u4s-(standard,highmem)-144-lssd	128	128	0	0	8
u4s-*-192 u4s-(standard,highmem)-192-lssd	128	128	0	0	8
u4s-*-288 u4s-(standard,highmem)-288-lssd	128	128	0	0	8

Disk performance limits for U4S instances

The performance limits for Titanium SSD and Hyperdisk attached disks are listed in the following table:

Titanium SSD

Instance machine type	Number of Titanium SSD disks	Total storage space (GiB)	Read IOPS	Write IOPS	Read throughput (MiB/s)	Write throughput (MiB/s)
u4s-*-4-lssd	1	375	150,000	75,000	625	330
u4s-*-8-lssd	1	375	150,000	75,000	625	330
u4s-*-16-lssd	2	750	300,000	150,000	1,250	660
u4s-*-24-lssd	4	1,500	600,000	300,000	2,500	1,320
u4s-*-32-lssd	5	1,875	750,000	375,000	3,125	1,650
u4s-*-48-lssd	8	3,000	1,200,000	600,000	5,000	2,640
u4s-*-96-lssd	16	6,000	2,400,000	1,200,000	10,000	5,280
u4s-*-144-lssd	16	6,000	2,400,000	1,200,000	10,000	5,280
u4s-*-192-lssd	32	12,000	4,800,000	2,400,000	20,000	10,560
u4s-*-288-lssd	48	18,000	7,200,000	3,600,000	30,000	15,840

Hyperdisk Balanced

Instance machine type	Maximum IOPS	Maximum throughput (MiB/s)
u4s-*-2	50,000	400
u4s-*-4 u4s-*-4-lssd	50,000	400
u4s-*-8 u4s-*-8-lssd	50,000	800
u4s-*-16 u4s-*-16-lssd	100,000	1,600
u4s-*-24 u4s-*-24-lssd	100,000	1,600
u4s-*-32 u4s-*-32-lssd	100,000	1,600
u4s-*-48 u4s-*-48-lssd	160,000	2,400
u4s-*-96 u4s-*-96-lssd	240,000	4,800
u4s-*-144 u4s-*-144-lssd	240,000	4,800
u4s-*-192 u4s-*-192-lssd	320,000	10,000
u4s-*-288 u4s-*-288-lssd	320,000	10,000

Hyperdisk Extreme

Instance machine type	Maximum IOPS	Maximum throughput (MiB/s)
u4s-*-96 u4s-*-96-lssd	350,000	5,000
u4s-*-144 u4s-*-144-lssd	350,000	5,000
u4s-*-192 u4s-*-192-lssd	440,000	10,000
u4s-*-288 u4s-*-288-lssd	440,000	10,000

For more information about performance limits, see the following:

• Hyperdisk limits per instance
• Performance limits by Hyperdisk type

Network support for U4S instances

U4S instances come with one physical NIC per instance, but you can configure multiple vNICs.

vCPUs	Driver	Internal IP egress bandwidth	External IP egress bandwidth
2	gVNIC	Up to 10 Gbps	Up to 7 Gbps
4	gVNIC	Up to 23 Gbps	Up to 7 Gbps
8	gVNIC	Up to 23 Gbps	Up to 7 Gbps
16	gVNIC	Up to 23 Gbps	Up to 7 Gbps
24	gVNIC	Up to 23 Gbps	Up to 7 Gbps
32	gVNIC	Up to 23 Gbps	Up to 7 Gbps
48	gVNIC	Up to 50 Gbps	Up to 25 Gbps
96	gVNIC	Up to 100 Gbps	Up to 25 Gbps
144	gVNIC	Up to 150 Gbps	Up to 25 Gbps
192	gVNIC	Up to 200 Gbps	Up to 25 Gbps
288	gVNIC	Up to 200 Gbps	Up to 25 Gbps

Regional availability of U4 machine types

Machine types for the U4 machine family are available in the following Google Cloud regions and zones:

• us-south1
  • us-south1-d
  • us-south1-e

U4 limitations

The U4 machine family doesn't support the following Compute Engine features:

• For Shielded VM features, see the following:

  • Secure Boot isn't supported for U4 instances.

    • U4 instances require an operating system image with an out-of-tree (OOT) gVNIC driver as described in Operating system support for U4 machine types. When Secure Boot is enabled, the operating system enforces strict kernel module signature verification. Because OOT drivers aren't signed with a recognized distribution key, Secure Boot prevents the network driver from loading, which causes network initialization to fail.

    • Additionally, Secure Boot prevents using Onload built from source as described in Work with Onload. Building Onload from source installs a custom kernel module. Because custom kernel modules built from source aren't signed with a recognized distribution key, Secure Boot prevents the Onload kernel module from loading.

  • Shielded VM isn't supported for bare metal instances as described in the limitations section of the Shielded VM overview.

  If your Google Cloud org uses a Shielded VM policy, then you must create a custom org policy that excludes U4 instances from the Shielded VM requirement.

• Confidential VM

• Sole-tenancy: Each U4P or U4C instance runs on a dedicated host server.

• Spot VMs

• Simulating host maintenance events

Additional limitations of U4 instances:

• For U4S, you can create only VM instances; bare metal instances aren't supported.
• U4P and U4C bare metal instances with the C6 CPU sleep state enabled have low single-stream NIC performance. You can disable the C6 CPU sleep state in the guest OS to achieve full network bandwidth performance. For more information, refer to the troubleshooting network performance documentation.

Quota limits for U4

CPU quota is the total number of virtual CPUs across all of your compute instances in a region or zone. CPU quotas apply to running instances and reservations. If your CPU quota is set to 16, then you can create a single compute instance with 16 vCPUs, or you can create 4 compute instances with 4 vCPUs each.

To understand Compute Engine quotas and resource allocation limits, and to learn how to view your U4 quotas, see Compute Engine quota and limits overview.

Quota Type	Machine Series	Quota Name	Limit/Description
CPU	U4C	CPUS_PER_VM_FAMILY: U4C	240 vCPUs per zone
CPU	U4S	CPUS_PER_VM_FAMILY: U4S	576 vCPUs per zone
Local SSD	All	N/A	No quota request needed; disks are added automatically to instances created by using U4 machine types that end in -lssd.
Google Cloud Hyperdisk	All	Hyperdisk Balanced Capacity (GB) Hyperdisk Balanced IOPS Hyperdisk Balanced Throughput (MB/s) Hyperdisk Extreme Capacity (GB)	Capacity and performance quotas apply. For more information, see Disk quotas.
Commitments	U4C	Committed_U4C_CPUS	Used with a resource-based, committed use contract
Commitments	U4S	Committed_U4S_CPUS	Used with a resource-based, committed use contract

If you require a quota increase you can reach out to your account teams or follow the instructions in Allocation quotas.

Operating system support for U4 machine types

This section describes the supported operating system (OS) images for U4 machine types.

Images from the following image families contain an out-of-tree (OOT) Google Virtual NIC (gVNIC) driver, which lets you create U4P and U4C bare metal instances with the GVNIC network interface type, as well as U4S VM instances. Additionally, the driver supports PTP, which lets you configure accurate time for U4 instances.

Note: The Operating system details page in the Compute Engine documentation provides general OS support information across Google Cloud for non-U4 machine types. To understand OS support for U4 machine types, use the following sections.

Windows images aren't supported.

Red Hat Enterprise Linux (RHEL) images

Google Cloud supports the following Red Hat Enterprise Linux (RHEL) OS images for U4 machine types:

• RHEL 10.2 EUS with out-of-tree gVNIC driver
  • Image project: rhel-cloud
  • Image family: rhel-10-2-eus-gvnic-baremetal or rhel-10-2-eus-lvm-gvnic-baremetal

Although the image family is appended with -baremetal, you also use this image family when creating U4S VM instances.

RHEL BYOS images

You can also create a U4 instance by using images from your Red Hat Cloud Access subscription. The general procedure is described in Create an instance using a RHEL BYOS image.

For bring your own subscription (BYOS) images, the image project and family are as follows:

• Image project: rhel-byos-cloud
• Image family: rhel-10-2-eus-gvnic-baremetal-byos or rhel-10-2-eus-lvm-gvnic-baremetal-byos

To use the BYOS image, you must complete an additional prerequisite as follows:

1. You must first give your Google Group access to your RHEL subscription as described in Create an instance using a RHEL BYOS image.

2. You can then follow the procedure to create a ULL instance or create a non-ULL instance by specifying the BYOS image project and family.

For additional information about BYOS, see About Licenses.

Rocky Linux images

Google Cloud supports the following Rocky Linux OS images for U4 machine types:

• Rocky Linux 10 optimized for Google Cloud with out-of-tree gVNIC driver
  • Image project: rocky-linux-cloud
  • Image family: rocky-linux-10-optimized-gcp-oot-gve

Custom images

Using custom images based on other Linux versions isn't supported.

What's next

• Create ULL Compute Engine instances
• Create non-ULL Compute Engine instances
• Learn about ULL infrastructure configuration
• Learn about ULL Multicast