Best practices for persistent disk snapshots
You can create persistent disk snapshots at any time, but you can create snapshots more quickly and with greater reliability if you use the following best practices.
Creating frequent snapshots efficiently
Use snapshots to manage your data efficiently.
Create a snapshot of your data on a regular schedule to minimize data loss due to unexpected failure.
Improve performance by eliminating excessive snapshot downloads and by creating an image and reusing it.
Set your snapshot schedule to off-peak hours to reduce snapshot time.
Snapshot frequency limits
Creating snapshots from persistent disks
You can snapshot your disks at most once every 10 minutes. If you want to issue a burst of requests to snapshot your disks, you can issue at most 6 requests in 60 minutes.
If the limit is exceeded, the operation fails and returns the following error:
https://cloud.google.com/compute/docs/disks/snapshot-best-practices