在服务器备份期间阻止付款

Question

I am working on a shopping website where users are redirected to paypal for payment.

On the server I have a scheduled backup task running once a month that last something like 15 minutes. During backup the website will be suspended.

However, if a user has just been redirected to paypal before my server is suspended then there is the risk of a user making a payment but the purchased items will not be stored in the DB since my server is suspended.

What are the options to handle this situation? Should I write a little PHP to prevent purchases already 10 minutes before server backup? Are there any other common options? Thanks!

Answer 1

If you'd like to prevent any downtime, you can have the purchase information stored in a queue, separate from the "main" server that you back up regularly and have a job that reads from that queue and store in your "main" server. Use a persistent queue that doesn't need to be backed up (as long as it is consumed as soon as possible) so it can be accepting data while your server is down.

Once your backup is done, the server can read whatever info there is stored in the queue and process it.

If you stop redirecting to PayPal 10 minutes before the backup, what would happen if a user has been redirected 11 minutes before the backup? What would happen if the backup took 2 minutes more than what you initially thought was a safe interval? Don't do that :)