Re: Unable to connect DB...?

Once, our developers had the bright idea of deleting files to quickly purge data.  Naturally, it corrupted everything, and points to the danger of developers having the postgres password...

Since your message says that the file is completely missing, someone must have deleted the file. There is nothing you can do except restoring from a backup.

Making sure postgres owns the files and the access rights are restricted to rw------- prevents this.

Even a file system error won't lead to this situation, as typically the file remains with length 0.