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:ESSD/SSD-based instances

Last Updated:Jul 05, 2024

This topic describes the specifications of Tair ESSD/SSD-based instances. The specifications include the memory capacity, maximum number of connections, and maximum bandwidth.

Instance specifications

The following table provides the specifications of a single shard.

  • The overall performance of a standard instance is determined by the specifications of the shard.

  • The overall performance of a cluster instance can be estimated by multiplying the performance of a single shard by the total number of shards in the instance.

    Note
    • Starting May 8, 2024, the maximum number of connections to each shard of an ESSD/SSD-based instance is increased to 60,000. This increase applies to both newly created and upgraded instances.

    • Instances that can be created in different regions and zones are subject to actual inventory.

Shard specifications of ESSD-based instances

ESSD-based instances support only the standard architecture.

Specification type

InstanceClass value (used in API operations)

Specifications

Maximum connections

Maximum bandwidth (Mbit/s)

CPU cores

Memory (GB)

Storage performance level and capacity range (GB)

4C - 16GB

tair.essd.standard.xlarge

4

16

PL1: 20 to 80

60,000

187.5

8C - 32GB

tair.essd.standard.2xlarge

8

32

PL1: 60 to 230

PL2: 470 to 750

60,000

250

16C - 64GB

tair.essd.standard.4xlarge

16

64

PL1: 60 to 460

PL2: 470 to 1,230

PL3: 1,270 to 2,160

60,000

375

32C - 96GB

tair.essd.standard.8xlarge

32

128

PL2: 470 to 2,160

PL3: 1,270 to 4,320

60,000

625

52C - 192GB

tair.essd.standard.13xlarge

52

192

PL2: 470 to 3,090

PL3: 1,270 to 6,150

60,000

1,000

Note

Enhanced SSDs at performance level 3 (PL3 ESSDs) perform better than PL2 and PL1 ESSDs. For more information, see ESSDs.

Shard specifications of SSD-based standard instances and cluster instances in direct connection mode

The following specifications apply to SSD-based standard instances and cluster instances in direct connection mode.

Specification type

InstanceClass value (used in API operations)

Specifications

Maximum connections

Maximum bandwidth (Mbit/s)

CPU cores

Memory (GB)

SSD capacity (GB)

4C-32GB

tair.localssd.c1m8.xlarge

4

32

640

60,000

187.5

8C-32GB

tair.localssd.c1m4.2xlarge

8

32

320

60,000

375

8C-64GB

tair.localssd.c1m8.2xlarge

8

64

1,280

60,000

312.5

16C-64GB

tair.localssd.c1m4.4xlarge

16

64

640

60,000

625

32C-128GB

tair.localssd.c1m4.8xlarge

32

128

1,280

60,000

1,500

Shard specifications of SSD-based cluster instances in proxy mode

The following specifications apply to SSD-based cluster instances in proxy mode.

Specification type

InstanceClass value (used in API operations)

Specifications

Maximum connections

Maximum bandwidth (Mbit/s)

CPU cores

Memory (GB)

SSD capacity (GB)

4C-32GB

tair.localssd.c1m8.with.proxy.xlarge

4

32

640

60,000

187.5

8C-32GB

tair.localssd.c1m4.with.proxy.2xlarge

8

32

320

60,000

375

8C-64GB

tair.localssd.c1m8.with.proxy.2xlarge

8

64

1,280

60,000

312.5

16C-64GB

tair.localssd.c1m4.with.proxy.4xlarge

16

64

640

60,000

625

32C-128GB

tair.localssd.c1m4.with.proxy.8xlarge

32

128

1,280

60,000

1,500

Performance description

Architecture

Performance description

Standard architecture

The overall performance of a standard instance is determined by the specifications of the corresponding instance type described in the preceding instance specification tables.

Cluster architecture in direct connection mode

Cluster architecture in proxy mode

Overall performance of an instance = Performance of a single shard × Number of shards.

Note

When a cluster instance that runs in proxy mode is accessed, the maximum bandwidth is 2,048 Mbit/s, the maximum total QPS is 10,000,000, and the maximum number of connections is 500,000.

For example, an instance that contains four shards of the tair.localssd.c1m4.with.proxy.2xlarge type has the following specifications:

  • Number of CPU cores: 8

  • Memory: 32 GB

  • SSD capacity: 320 GB

  • Number of connections: 60,000

  • Bandwidth: 375 Mbit/s

In this case, the instance provides the following performance:

  • Number of CPU cores: 32

  • Memory: 128 GB

  • SSD capacity: 1,280 GB

  • Number of connections: 240,000

  • Bandwidth: 1,500 Mbit/s

Notes about CPU cores

To ensure service stability, the system reserves a CPU core to process background tasks. In a cluster instance or a read/write splitting instance, the system reserves a CPU core for each data shard or each read replica to process background tasks.

Bandwidth description

  • Each bandwidth value in the preceding tables represents the maximum bandwidth of a single shard. The total bandwidth of a cluster or read/write splitting instance is the combined bandwidth of all shards in the instance.

  • The maximum bandwidth of cluster instances in proxy mode is 2,048 Mbit/s. If the limit is reached, the bandwidth of an instance cannot be increased by adding shards. Cluster instances in direct connection mode have no bandwidth limit.

  • The bandwidth applies to upstream and downstream bandwidths. For example, if the bandwidth of an instance is 375 Mbit/s, the upstream and downstream bandwidths of the instance are both 375 Mbit/s.

  • The bandwidth limits of Tair and Redis refer to the data transfer capacity of individual shards within their respective distributed systems. The limits are generally independent of the network connection types used by clients to connect to the shards.

For information about the FAQ about bandwidth, see FAQ about bandwidth.

Calculation rules for connections

Item

Description

Maximum number of connections

  • Proxy mode: 500,000. If the upper limit of 500,000 connections is reached, subsequent connections cannot be established even when you add more shards.

  • Direct connection mode: Maximum number of connections to an instance = Maximum number of connections to a shard × Number of shards.