If you have your own S3 account you can configure it in the config/config.json file. You should just need to go to the AWSSettings section and fill in the follow fields:
Once those are configured properly you should be able to start uploading/downloading images and files to your S3 bucket through your Mattermost instance. (Make sure to restart your server after filling these in).
As it is now we don’t have any way to allow you to configure local server storage, but this is something that’s on our roadmap of things to add
I have created aws account and provided access and secrety key,bucket name and region but i am getting below error when i try to upload the file .
Unable to upload file. The bucket you are attempting to access must be addressed using the specified endpoint. Please send all future requests to this endpoint.XXXXXXXXXXXXXXXXX
It seems like an S3 configuration issue, propose trying the new release candidate that offers local storage: http://www.mattermost.org/mattermost-v0-6-0-rc2/
We’d highly appreciate your feedback, if there are any issues we missed, there’s potentially time to address them before the final release on Friday,