Code Storage - Does it reuse a deployment package?

Question

Hello,  
  
I have several functions using same deployment package, like this:

```
...
    "DeleteDashuserLambdaFunction": {
      "Type": "AWS::Lambda::Function",
      "Properties": {
        "Code": {
          "S3Bucket": "dev.eu-west-1.serverless.deploys.em.com",
          "S3Key": "serverless/user-service-ts/dev/1554451324595-2019-04-05T08:02:04.595Z/user-service-ts.zip"
        },
...
    "InviteDashuserLambdaFunction": {
      "Type": "AWS::Lambda::Function",
      "Properties": {
        "Code": {
          "S3Bucket": "dev.eu-west-1.serverless.deploys.em.com",
          "S3Key": "serverless/user-service-ts/dev/1554451324595-2019-04-05T08:02:04.595Z/user-service-ts.zip"
        },
...
```

Will the lambda reuse the deployment package? What's more effective from the code storage perspective: use one zip (say 10MB) for several functions or split into smaller zips (10 packages 5 MB each)?

Accepted Answer

Hi there!  
  
> Will the lambda reuse the deployment package?  
  
Lambda will not reuse the same deployment package. When the Lambda function is deployed, it creates a copy of the code referenced in the S3 bucket for each function.  
  
> What's more effective from the code storage perspective: use one zip (say 10MB) for several functions or split into smaller zips (10 packages 5 MB each)?  
  
It is always recommended to have a smaller deployment package for each Lambda function. While there is no direct advantage with respect to code storage, this provides multiple advantages such as reduced cold start times and the ability to edit code inline. More details can be found here:  
https://docs.aws.amazon.com/lambda/latest/dg/best-practices.html

Code Storage - Does it reuse a deployment package?

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