ServiceStack.Net Redis: Storing Related Objects vs. Related Object Ids

Question

My team has decided to work with Redis via the ServiceStack.net Redis Client as an underlying repository for a new high-volume website we're working on. I'm not really sure where to look for documentation for this question (either for general Redis docs or specific ServiceStack.Net docs or both) - is there actually a definitive source for documentation on how to implement a Redis via ServiceStack.Net that includes all you need to know about both Redis concepts and ServiceStack.Net concepts, or do we need to integrate documentation from both aspects separately to get the full picture?.

I'm just grappling with how exactly to store related objects in our model's object graph. Here's a simple scenario that I want to work with:

There are two objects in the system: User and Feed. In RDBMS terms these two objects have a one-to-many relationship, that is, a User has a collection of Feed objects and a feed can only belong to one User. Feeds will always be accessed from Redis via their user but occasionally we'll want to get access to the user via a feed instance.

So the question I have is whether we should be storing the related objects as properties or should we store the Id values of the related objects? To illustrate:

Approach A:

public class User
{
    public User()
    {
        Feeds = new List<Feed>();
    }

    public int Id { get; set; }

    public List<Feed> Feeds { get; set; }

    // Other properties
}

public class Feed
{
    public long Id { get; set; }

    public User User { get; set; }
}

Approach B:

public class User
{
    public User()
    {
        FeedIds = new List<long>();
    }

    public long Id { get; set; }

    public List<long> FeedIds { get; set; } 

    public List<Feed> GetFeeds()
    {
        return repository.GetFeeds( FeedIds );
    }
}

public class Feed
{
    public long Id { get; set; }

    public long UserId { get; set; }

    public User GetUser()
    {
        return repository.GetUser( UserId );
    }
}

Which of the above approaches will work best? I've seen both approaches used in various examples but I get the impression that some of the examples I've seen may not be best-practice.

A few simple related questions:

• If I make a change to an object will it automatically be reflected in Redis or will it require a save? I'm assuming the latter, but need to be absolutely clear.
• If I (can) use Approach A, will an update to User object X be reflected throughout the entire object graph wherever it is referenced or will it be necessary to save changes across the graph?
• Is there a problem with storing an object via it's interface (i.e. use IList<Feed> as opposed to List<Feed>?

Sorry if these questions are a little basic - until 2 weeks ago I'd never even heard of Redis - let alone ServiceStack - (nor had anyone in my team) so we're really starting from scratch here...