A legal separation does not end a marriage or domestic partnership. You cannot marry or enter into a partnership with someone else if you are legally separated (and not divorced). A legal separation is for couples that do not want to get divorced but want to live apart and decide on money, property, and parenting issues. Couples sometimes prefer separation for religious reasons.
You do not need to meet California's residency requirement to file for a legal separation. If you file for a legal separation, you may later be able to file an amended petition to ask the Court for a divorce-after you meet the residency requirements.
In a legal separation case, you can ask the Judge for orders like child support, spousal support, partner support, custody and visitation, domestic violence restraining orders, or any other orders you can get with a divorce case.
More information on separation is available here.