I encountered a production database of 12 GB with a log of 90 GB. Full and differential database backups are made with a third-party backup tool, but no one is backing up the transaction log so it got way out of hand in the past year.
Now I want to fix the situation by first doing a full backup from SQL Server and then doing a transaction log backup. There is not much space on the server, so I'd like to know in advance how big the transaction log backup will be, approximately. I understand that the transaction log will only be truncated after backup, so I'm afraid the backup will be 90 GB as well and clogg the server.
So far I can't find any information on backup sizes, can someone explain what will happen size-wise? Thanks in advance!
SQL Server version is Standard Edition, and the database recovery model is full.