Legal Question in Personal Injury in California

It really depends on what it is you want to prove, and whether subpoenaing the server's records would be worthwhile or cost-effective under all the circumstances. If you're trying to prove you weren't served properly, in most cases you are better off just responding to the lawsuit than trying to challenge the adequacy of service. However, one would have a valid lawsuit against a server who filed false proofs of service; if the damages were significant, in such a lawsuit one could theoretically subpoena the types of documents you mentioned. If the stakes were sufficiently high it might even be worthwhile to subpoena cell phone tower records that, of course, track the movements of every cell phone subscriber. I'm not aware that process servers are required to, or that they do, routinely log GPS coordinates. Some employers (for example trucking companies) do GPS-track their employees, so anything's possible. Consult a lawyer and watch out for legal time limits.