# Tuning performance

## Memory Usage

This chapter describes configuration options related to the memory consumption of a connector service.

### Hard limit

#### Description

* Specifies the maximum commit size, in bytes, for the GC heap and GC bookkeeping.
* This setting only applies to 64-bit computers.
* This setting is ignored if the [Per-object-heap limits](https://docs.microsoft.com/en-us/dotnet/core/runtime-config/garbage-collector#per-object-heap-limits) are configured.
* The default value, which only applies in certain cases, is the greater value of 20 MB or 75% of the memory limit on the container. The default value applies if:
  * The Connector Service is running inside a container that has a specified memory limit.
  * [System.GC.HeapHardLimitPercent](https://docs.microsoft.com/en-us/dotnet/core/runtime-config/garbage-collector#heap-limit-percent) is not set.

#### How to activate

* Open the installation folder for the Connector Service that you want to configure.
* Open the Novacura.Connector.MyConnector.runtimeconfig.json in a proper text editor such as VSCode or Notepad++ (create the file if it does not exist, noting that "MyConnector" must be replaced with the actual connector name).
* Locate "runtimeOptions" and add "**System.GC.HeapHardLimit**" to the "configProperties" array (note that the key-value pairs are comma separated).

```
{
   "runtimeOptions": {
      "configProperties": {
         "System.GC.Server": true,
         "System.GC.HeapHardLimit": 2097152000,
         "SomeOtherKey": "Comma separated key/value pairs above..."
      }
   }
}
```

{% hint style="success" %}
1 Mebibyte (MiB) = 1 048 576 (2^20 = 1024^2) bytes. For example, to specify a heap hard limit of 2000 mebibytes (MiB), the value would be 2 097 152 000.
{% endhint %}

### Percentage limit

#### Description

* Specifies the allowable GC heap usage as a percentage of the total physical memory.
* If [System.GC.HeapHardLimit](https://docs.microsoft.com/en-us/dotnet/core/runtime-config/garbage-collector#heap-limit) is also set, this setting is ignored.
* This setting only applies to 64-bit computers.
* If the Connector Service is running inside a container that has a specified memory limit, the percentage is calculated as a percentage of that memory limit.
* This setting is ignored if the [Per-object-heap limits](https://docs.microsoft.com/en-us/dotnet/core/runtime-config/garbage-collector#per-object-heap-limits) are configured.
* The default value, which only applies in certain cases, is the greater value of 20 MB or 75% of the memory limit on the container. The default value applies if:
  * The Connector Service is running inside a container that has a specified memory limit.
  * [System.GC.HeapHardLimit](https://docs.microsoft.com/en-us/dotnet/core/runtime-config/garbage-collector#heap-limit) is not set.

#### How to activate

* Open the installation folder for the Connector Service that you want to configure.
* Open the Novacura.Connector.MyConnector.runtimeconfig.json in a proper text editor such as VSCode or Notepad++ (create the file if it does not exist, noting that "MyConnector" must be replaced with the actual connector name).
* Locate "runtimeOptions" and add "**System.GC.HeapHardLimitPercent**" to the "configProperties" array (note that the key-value pairs are comma separated).

```
{
   "runtimeOptions": {
      "configProperties": {
         "System.GC.Server": true,
         "System.GC.HeapHardLimitPercent": 30,
         "SomeOtherKey": "Comma separated key/value pairs above..."
      }
   }
}
```

{% hint style="success" %}
For example, to limit the heap usage to 30%, the value would be 30.
{% endhint %}