Limits - FPGA as a Service - Alibaba Cloud Documentation Center

From a resource management standpoint, FPGA-accelerated instances are considered as Elastic Compute Service (ECS) instances. Limits to ECS instances are also applicable to FPGA-accelerated instances. This topic describes the limits to ECS and how to apply for extensions on these limits.

Overview

ECS has the following limits:

Only ECS Bare Metal Instance families and Super Computing Cluster (SCC) instance families support secondary virtualization, and other ECS instance families do not support the installation of virtualization software and secondary virtualization.
ECS does not support sound card applications.
External hardware devices, such as hardware dongles, USB flash drives, external hard disks, and bank U keys, cannot be directly attached to ECS instances. Software verification methods, such as software dongles and two-factor authentication based on one-time passwords, can be used.
ECS does not support multicast protocols. We recommend that you use unicast protocols instead.
Log Service does not support 32-bit Linux ECS instances.
For more information about the ECS instances supported by Log Service, see Install Logtail on a Linux server and Install Logtail on a Windows server.
To apply for Internet Content Provider (ICP) filings for websites that are deployed on your ECS instances, make sure that the instances meet ICP filing requirements. You can apply for only a limited number of ICP filing service identification numbers for each ECS instance. For more information, see Prepare and check the instance and access information.
Specific software or application licenses must be bound to the hardware of ECS instances. After data is migrated from one instance to another, hardware information may change and invalidate the licenses.

Instance limits


Item	Requirement or limit	Adjustable
Permissions to create ECS instances	To create ECS instances within the Chinese mainland, you must first complete real-name verification.	N/A
Instances of a specific instance type, billing method, and network type within a specific zone	You can view the instance quota in the ECS console. For more information, see View and increase instance quotas.	You can apply for a quota increase in the ECS console. For more information, see View and increase instance quotas.
Maximum number of subscription instances that you can purchase at a time	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	N/A
Maximum number of launch templates per region within an account	30	N/A
Maximum number of versions of a single launch template	30	N/A
Permissions to change the billing method from pay-as-you-go to subscription	You cannot change the billing method of instances of retired instance types from pay-as-you-go to subscription. For more information, see Retired instance types.	N/A
Permissions to change the billing method from subscription to pay-as-you-go	Your ECS usage determines whether the billing method of instances can be changed from subscription to pay-as-you-go. If you change the billing method from subscription to pay-as-you-go, a refund may be made. Each account has a maximum monthly refund amount. Details of the refund are displayed on the Switch to Pay-As-You-Go page in the ECS console.	N/A

Reserved instance limits


Item	Requirement or limit	Adjustable
Maximum number of regional reserved instances within an account	20	Submit a ticket.
Maximum number of zonal reserved instances per zone within an account	20	Submit a ticket.
Instance types that support reserved instances	The following instance families support reserved instances: General-purpose instance families: g7, g7a, g6e, g6, g5, g5ne, and sn2ne Compute-optimized instance families: c7, c7a, c6e, c6, c5, ic5, and sn1ne Memory-optimized instance families: r7, r7a, r6e, r6, r5, re6, re4, and se1ne Big data instance family: d2s Instance families with local SSDs: i3, i3g, i2, i2g, and i2gne Instance families with high clock speeds: hfg7, hfc7, hfr7, hfg6, hfc6, hfr6, hfg5, and hfc5 GPU-accelerated compute-optimized instance families: gn7, gn6i, gn6e, gn6v, gn5, and gn5i ECS Bare Metal Instance families: ebmgn7, ebmgn6i, ebmgn6e, ebmg6, ebmc6, ebmr6, ebmhfg6, ebmhfc6, and ebmhfr6 Burstable instance families: t6 and t5	N/A

Note For more information about the reserved instance limits, see the "Limits" section in Overview.

Savings plan limits


Item	Requirement or limit	Adjustable
Maximum number of savings plans within an account	40	N/A
Instance types that support savings plans	Savings plans cannot be applied to instances of retired Generation I instance families, which include t1, s1, s2, s3, m1, m2, c1, and c2.	N/A

EBS limits


Item	Requirement or limit	Adjust the quota
Permissions to create pay-as-you-go disks	To create disks within the Chinese mainland, you must first complete real-name verification.	N/A
Maximum number of pay-as-you-go disks	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	N/A
Maximum number of system disks on a single instance	1	N/A
Maximum number of data disks on a single instance	64 Note You can attach up to 16 data disks to an instance when you create the instance. If the instance requires more data disks, attach more data disks after the instance is created. The maximum number of disks that can be attached to an instance varies with instance types. For more information, see Overview of instance families.	N/A
Capacity of all pay-as-you-go ultra disks within an account	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	N/A
Capacity of all pay-as-you-go standard SSDs within an account	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	N/A
Capacity of all pay-as-you-go enhanced SSDs (ESSDs) within an account	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	N/A
Capacity of a single basic disk	5 GiB~2,000 GiB	N/A
Capacity of a single standard SSD	20 GiB~32,768 GiB	N/A
Capacity of a single ultra disk	20 GiB~32,768 GiB	N/A
Capacity of a single ESSD	PL0 ESSDs: 40 GiB to 32,768 GiB PL1 ESSDs: 20 GiB to 32,768 GiB PL2 ESSDs: 461 GiB to 32,768 GiB PL3 ESSDs: 1,261 GiB to 32,768 GiB	N/A
Capacity of a single ESSD AutoPL disk	40 GiB~32,768 GiB	N/A
Capacity of a single local standard SSD	5 GiB~800 GiB	N/A
Capacity of all local standard SSDs on an instance	1,024 GiB	N/A
Capacity of a single system disk	Windows Server: 40 GiB to 2,048 GiB Red Hat: 40 GiB to 2,048 GiB CoreOS and FreeBSD: 30 GiB to 2,048 GiB Linux distributions excluding CoreOS: 20 GiB to 2,048 GiB Note Basic disks are the previous generation of disks that are unavailable for purchase. If you use basic disks as system disks, the capacity upper limit for each basic disk is 500 GiB.	N/A
Permissions to attach new local disks to instances that are equipped with local disks	New local disks cannot be attached to instances that are already equipped with local disks.	N/A
Permissions to change configurations of instances that are equipped with local disks	Only bandwidth configurations of instances that are equipped with local disks can be changed.	N/A
Mount points of system disks	/dev/vda	N/A
Mount points of data disks	/dev/vd[b-z]	N/A

Note The capacity of Elastic Block Storage (EBS) devices is measured in binary units. In binary units, 1 KiB equals 1,024 bytes. Example: 1 GiB = 1,024 MiB.

SCU limits


Item	Requirement or limit	Adjustable
Maximum capacity that you can purchase for a storage capacity unit (SCU)	50 TiB	Submit a ticket.
Maximum number of SCUs that you can purchase within a region	100	N/A
Resource types that support SCUs	ESSDs, standard SSDs, ultra disks, and basic disks Apsara File Storage NAS Capacity and NAS Performance Normal snapshots Object Storage Service (OSS) Standard, Infrequent Access, and Archive storage classes Hybrid Backup Recovery (HBR) backup storage capacity	N/A

Snapshot limits


Item	Requirement or limit	Adjustable
Maximum number of manual snapshots that can be retained for a single disk	256	N/A
Maximum number of automatic snapshots that can be retained for a single disk	1,000	N/A
Maximum number of automatic snapshot policies that can be created per region within an account	100	N/A

Image limits


Item	Requirement or limit	Adjustable
Images within an account	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	You can apply for a quota increase in the ECS console. For more information, see View and increase resource quotas.
Maximum number of users to whom a single image can be shared	50	Submit a ticket.
Support of instance types for images	Instance types that have 4 GiB or larger memory do not support 32-bit images.	N/A

SSH key pair limits


Item	Requirement or limit	Adjustable
Maximum number of SSH key pairs per region within an account	500	N/A
Instance types that support SSH key pairs	Non-I/O optimized instances of Generation I instance families do not support SSH key pairs.	N/A
Images that support SSH key pairs	Linux images only.	N/A

Public bandwidth limits

As of November 27, 2020, the maximum bandwidth value available for you to create ECS instances or change the configurations of ECS instances is subject to the throttling policy for your account. To increase the maximum bandwidth value, submit a ticket. The following throttling policies apply:

Within a single region, the sum of actual maximum bandwidths of all ECS instances that use the pay-by-traffic billing method for network usage cannot exceed 5 Gbit/s.
Within a single region, the sum of actual maximum bandwidths of all ECS instances that use the pay-by-bandwidth billing method for network usage cannot exceed 50 Gbit/s.


Item	Requirement or limit	Adjustable
Maximum inbound bandwidth per instance	If the purchased maximum outbound bandwidth is less than or equal to 10 Mbit/s, Alibaba Cloud allocates an inbound bandwidth of 10 Mbit/s. If the purchased maximum outbound bandwidth is greater than 10 Mbit/s, Alibaba Cloud allocates an inbound bandwidth that is equal to the purchased maximum outbound bandwidth.	N/A
Maximum outbound bandwidth per instance	Subscription instance: 200 Mbit/s Pay-as-you-go instance: 100 Mbit/s	N/A
Changes of the assigned public IP address of an instance	The public IP address of an instance can be changed within 6 hours after the instance is created and can be changed up to three times.	N/A

Important When the pay-by-traffic billing method for network usage is used, the maximum inbound and outbound bandwidth values are used as upper limits of bandwidths instead of guaranteed performance specifications. In scenarios where demand outstrips resource supplies, these maximum bandwidth values may be reached. If you want guaranteed bandwidths for your instance, use the pay-by-bandwidth billing method for network usage.

Security group limits


Item	Requirement or limit on basic security groups	Requirement or limit on advanced security groups
Maximum number of security groups per region within an account	You can view the resource quota in the ECS console ^①. For more information, see View and increase resource quotas.	This limit is the same as that on basic security groups.
Maximum number of ECS instances of the classic network type that can be contained in a security group of the classic network type	1,000 ^②	The classic network is not supported.
Maximum number of ECS instances of the Virtual Private Cloud (VPC) type that can be contained in a security group of the VPC type	This limit varies based on the number of private IP addresses that can be contained in the security group of the VPC type.	No limit.
Maximum number of security groups to which an ECS instance can belong	5 You can submit a ticket to raise the limit to 4 or 10 security groups. In this case, the maximum number of rules that can be added to each security group is adjusted accordingly.^③	The limit is the same as that on basic security groups.
Maximum number of security groups to which an elastic network interface (ENI) of an ECS instance can belong		The limit is the same as that on basic security groups.
Maximum number of inbound and outbound rules in a security group	200 ^③	This limit is the same as that on basic security groups.
Maximum number of inbound and outbound rules in all security groups to which an ENI belongs	1,000	This limit is the same as that on basic security groups.
Maximum number of rules that reference security groups as authorization objects (sources or destinations) in a security group	20	0. You cannot add rules that reference security groups as authorization objects (sources or destinations) to an advanced security group, or reference advanced security groups as authorization objects (sources or destinations) in rules.
Maximum number of private IP addresses that can be contained in a security group of the VPC type	2,000 ^④. You can apply to raise the limit to 6,000. Note You can go to the Quota Center console and find the The maximum number of private IP addresses in the general security group of the VPC quota to request a quota increase. For more information, see Submit an application to increase a quota.	65,536
Internet access port	For security purposes, port 25 is disabled on ECS instances by default. We recommend that you use the SSL port instead to send emails. In most cases, the SSL port is port 465.	The requirement is the same as that on basic security groups.

^① The following regions share the quota for the number of security groups that can be created within each account: China (Hangzhou), China (Shanghai), China (Qingdao), China (Beijing), China (Shenzhen), China (Hong Kong), US (Silicon Valley), and Singapore. A maximum of 100 security groups can be created in all of these regions within an account.
^② If more than 1,000 instances of the classic network type need mutual access over the internal network, you can assign them to multiple security groups and allow mutual access among these security groups.
^③ If you increase the quota for the number of security groups per ECS instance, the quota for the number of rules in each security group decreases. The product of the following quotas cannot exceed 1,000: the quota for the number of security groups per ECS instance and the quota for the number of rules in each security group. For example, if the quota for the number of security groups per ECS instance is 4, 5, or 10, the corresponding quota for the number of rules in each security group is 250, 200, or 100, as verified by using the following formulas: 4 × 250 = 1000, 5 × 200 = 1000, and 10 × 100 = 1000.
If prefix lists are referenced in security group rules, the maximum numbers of entries in the prefix lists count towards the quota for security group rules. For example, assume that a prefix list can contain a maximum of 100 entries. If the prefix list is referenced in a security group rule, the prefix list counts as 100 rules for the security group, regardless of the number of existing entries in the prefix list.
^④ If more than 2,000 private IP addresses need mutual access over the internal network, you can distribute ECS instances that have these private IP addresses to multiple security groups and allow mutual access among these security groups. You can also apply for a quota increase based on your needs in the supported regions.

Prefix list limits


Item	Limit	Adjustable
Maximum number of prefix lists per region within an account	100	N/A
Maximum number of entries in a single prefix list	200	N/A
Maximum number of associated resources of a prefix list	1,000	N/A

Network Connectivity Diagnostics limits


Item	Limit	Adjustable
Maximum number of diagnostic paths within a single region	100	N/A
Maximum number of diagnostic tasks within a single region	1,000	N/A
Maximum number of diagnostic tasks that can be concurrently executed within a single region	5	N/A

Deployment set limits


Item	Requirement or limit	Adjustable
Deployment sets within an account	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	You can apply for a quota increase in the ECS console. For more information, see View and increase resource quotas.
Maximum number of instances that can be contained in a single deployment set	A maximum of 20 instances can be contained in a deployment set within a single zone. The number of instances contained in a deployment set within a region is calculated by using the following formula: 20 × Number of zones in the region.	N/A
Instance types that support deployment sets	g8m, c7, g7, g7ne, r7, c6, g6, r6, c5, g5, r5, c6e, g6e, r6e, c7se, g7se, r7se, r6se, c7t, g7t, r7t, c7a, g7a, r7a, c6a, g6a, r6a, g5ne, re6, re6p, re4, and ic5 hfc7, hfg7, hfr7, hfc6, hfg6, hfr6, hfc5, and hfg5 d2s, d2c, d1, d1ne, d1-c14d3, and d1-c8d3 i3, i3g, i2, i2g, i2ne, i2gne, and i1 se1ne, sn1, sn1ne, sn2, sn2ne, and se1 ebmg5, sccgn6, scch5, sccg5, scch5s, and sccg5s s6, t6, xn4, mn4, n2, n1, and n4 gn6i	N/A

Cloud Assistant limits


Item	Limit	Adjustable
Maximum number of Cloud Assistant commands within an account	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	N/A
Retention period of a Cloud Assistant command output	28 days	N/A
Maximum number of Cloud Assistant command outputs that can be retained	100,000	N/A
Maximum number of the activation codes of a Cloud Assistant managed instance	5,000	N/A

ENI limits


Item	Limit	Adjustable
Maximum number of secondary ENIs that you can create	You can view the resource quota in the ECS console. For more information, see View and increase resource quotas.	N/A

Tag limits


Item	Limit	Adjustable
Maximum number of tags that can be added to a single instance	20	N/A

API


Item	Limit	Adjustable
Maximum number of calls of the CreateInstance operation	200 calls per minute	N/A

Note For information about the limits on VPCs, see Limits and quotas.