What can cause drastic traffic jump on server?

srgb asked:

In the last couple of days, between 3AM and 4AM my server traffic jumps tenfold, from 20MB to 200MB.

enter image description here

I’ve checked the access log, and while there is significant googlebot activity, the difference is not so drastic in the mentioned period compared to other periods of the day. I couldn’t find anything else in the access log that would indicate a problem.
I also checked sendmail log and nothing there either.

I will now sweep the access log for singular URLs that might have caused this, but in the mean time, were else can I check? What can I do to hunt this down?


My answer:

That has all the hallmarks of a nightly backup.

View the full question and any other answers on Server Fault.

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.