Managing Performance and Scaling for Amazon Aurora MySQL
Scaling Aurora MySQL DB Instances
You can scale Aurora MySQL DB instances in two ways, instance scaling and read scaling. For more information about read scaling, see Read Scaling.
You can scale your Aurora MySQL DB cluster by modifying the DB instance class for each DB instance in the DB cluster. Aurora MySQL supports several DB instance classes optimized for Aurora. The following table describes the specifications of the DB instance classes supported by Aurora MySQL.
| Instance Class | vCPU | ECU | Memory (GiB) |
|---|---|---|---|
|
db.t2.small |
1 |
1 | 2 |
|
db.t2.medium |
2 |
2 | 4 |
|
db.r3.large |
2 |
6.5 | 15.25 |
|
db.r3.xlarge |
4 |
13 | 30.5 |
|
db.r3.2xlarge |
8 |
26 | 61 |
|
db.r3.4xlarge |
16 |
52 | 122 |
|
db.r3.8xlarge |
32 |
104 | 244 |
|
db.r4.large |
2 |
7 | 15.25 |
|
db.r4.xlarge |
4 |
13.5 | 30.5 |
|
db.r4.2xlarge |
8 |
27 | 61 |
|
db.r4.4xlarge |
16 |
53 | 122 |
|
db.r4.8xlarge |
32 |
99 | 244 |
|
db.r4.16xlarge |
64 |
195 | 488 |
Maximum Connections to an Aurora MySQL DB Instance
The maximum number of connections allowed to an Aurora MySQL DB instance is determined
by
the max_connections parameter in the instance-level parameter group for
the DB instance.
The following table lists the resulting default value of
max_connections for each DB instance class available to Aurora MySQL. You
can increase the maximum number of connections to your Aurora MySQL DB instance by
scaling
the instance up to a DB instance class with more memory, or by setting a larger
value for the max_connections parameter, up to 16,000.
| Instance Class | max_connections Default Value |
|---|---|
|
db.t2.small |
45 |
|
db.t2.medium |
90 |
|
db.r3.large |
1000 |
|
db.r3.xlarge |
2000 |
|
db.r3.2xlarge |
3000 |
|
db.r3.4xlarge |
4000 |
|
db.r3.8xlarge |
5000 |
|
db.r4.large |
1000 |
|
db.r4.xlarge |
2000 |
|
db.r4.2xlarge |
3000 |
|
db.r4.4xlarge |
4000 |
|
db.r4.8xlarge |
5000 |
|
db.r4.16xlarge |
6000 |
If you create a new parameter group to customize your own default for the connection
limit, you'll see that the default
connection limit is derived using a formula based on the DBInstanceClassMemory value. As shown in the preceding
table, the formula produces connection limits that increase by 1000 as the memory
doubles between progressively larger R3 and R4
instances, and by 45 for different memory sizes of T2 instances. The much lower connectivity
limits for T2 instances are because T2
instances are intended only for development and test scenarios, not for production
workloads. The default connection limits are
tuned for systems that use the default values for other major memory consumers, such
as the buffer pool and query cache. If you
change those other settings for your cluster, consider adjusting the connection limit
to account for the increase or decrease in
available memory on the DB instances.
