Re: How to synchronize alf_data/contentstore to database
There is no way to recreate the database from only the contentstore. The contentstore only contains the (binary) contents of files, and no information as to their relationship, access permissions, metadata, or groups/user accounts etc. You can't even reconstruct the most basic detail such as name + (logical) path within Alfresco from a file in the contentstore. That is why backing up your database is an essential task to ensure you have access to the majority of your data after something unforeseen happens (like the loss of the live database).
I am sorry to not have better news / suggestions for you, but there is IMHO no hope of getting your system back up without a backup. Depending on what kind of files you had in your system and any filing rules that might have been in place, the most one could achieve with some intensive forensic work is identify the type of each file and extract a "likely" name from it, if its name was based on some intrinsic value (e.g. names of stored emails are derived from the subject, some Office files may contain title / file name as embedded metadata). If your system was set up to store files in encrypted form (unlikely for your version), you would not even be able to do that, and could not even access any of the files ever without spending significant amounts of efforts into cracking encryption keys.